1405 lines
47 KiB
HTML
1405 lines
47 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
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<HTML>
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<HEAD>
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<TITLE>Galapagos - Programmer's Manual</TITLE>
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<META NAME="Author" CONTENT="">
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<META NAME="GENERATOR" CONTENT="Mozilla/3.01Gold (Win95; I) [Netscape]">
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</HEAD>
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<BODY background=stone.jpg>
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<CENTER>
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<A href="implementation.html"><IMG border=0 src=prev.gif ALT=" [PREV] "></A>
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<A href="bib.html"><IMG border=0 src=next.gif ALT=" [PREV] "></A>
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<A href="index.html#toc"><IMG border=0 src=toc.gif ALT=" [PREV] "></A>
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</CENTER>
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<HR width=80% align=right color=blue>
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<P>
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<H1 ALIGN=CENTER><A NAME="top"></A>PROGRAMMER'S MANUAL:<BR>
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NONSTANDARD PRIMITIVES</H1>
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<UL>
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<LI><A HREF="manual.html#ENVIRONMENTS">Environments</A></LI>
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<LI><A HREF="manual.html#MESSAGE">Message Queues</A></LI>
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<LI><A HREF="manual.html#WINDOW">Window Commands</A></LI>
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<LI><A HREF="manual.html#TURTLE">Turtle Commands</A></LI>
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<LI><A HREF="manual.html#VISION">Vision</A></LI>
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<LI><A HREF="manual.html#INTERRUPTS">Interrupts (Notifications)</A></LI>
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<LI><A HREF="manual.html#THREADS">Threads</A></FONT></B><BR></LI>
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</UL>
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<P>
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<HR WIDTH="100%"></P>
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<P><FONT FACE="Tms Rmn">Welcome to Galapagos Scheme. This chapter is intended
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as a quick reference to Galapagos's extensions over traditional Scheme.
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Knowledge of Scheme is assumed. Galapagos Scheme is compliant with both
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</FONT>R4RS and IEEE standard P1178. If you've read the chapter titled
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"Scheme extensions", you can and should skip the short introduction
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in each section. This complete chapter appears as on-line help in Galapagos,
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just a F1 click away.<BR>
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</P>
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<H2>
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<HR WIDTH="100%"></H2>
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<H2><A NAME="ENVIRONMENTS"></A>ENVIRONMENTS<BR>
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</H2>
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<P><FONT FACE="Tms Rmn">An <I>environment</I> is a list of <I>frames</I>,
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with the <I>global environment</I> in its tail. A <I>frame</I> is a list
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of <I>bindings</I>, which map variables to their values. <I><FONT COLOR="#808080">(define...)
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</FONT></I>adds a binding to the frame at the top of the current environment.
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<I><FONT COLOR="#808080">(set!...) </FONT></I>family of commands modify
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an existing binding, in the frame where it was defined. When a variable
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is referenced, the current environment is searched from head to tail, and
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the first binding found dictates the value of the variable.</FONT> </P>
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<P><FONT FACE="Tms Rmn">The first interpreter, which pops up as Galapagos
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is started, runs at the global environment (the way traditional Scheme
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works). Additional interpreters (threads) run at distinct environments,
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which contain a single initially empty frame, and a pointer to the global
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environment. </FONT><BR>
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<BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(clone-environment
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env [depth]) </FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Clone-environment will make an exact copy of the
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environment <B><FONT COLOR="#008080">env</FONT></B>, by copying its frames
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one by one. If depth is specified then the new environment will be the
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collection of frames which is up to <B><FONT COLOR="#008080">depth</FONT></B>
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frames from the current frame. And the last frame will point to the <B><FONT COLOR="#008080">depth
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+ 1 </FONT></B>frames from the current one in <B><FONT COLOR="#008080">env</FONT></B>.<B><FONT COLOR="#008080">
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</FONT></B></FONT><BR>
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</P>
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<P><FONT FACE="Tms Rmn">This means that if we are now in environment <B><FONT COLOR="#008080">e1</FONT></B>
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and done <I><FONT COLOR="#808080">(define x 7).</FONT></I> Then if we'll
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write </FONT></P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define e2 (clone-environment
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(current-environment))),</FONT></FONT></I> </P>
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<P><FONT FACE="Tms Rmn">the result of</FONT> </P>
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<P><FONT FACE="Tms Rmn"><I><FONT COLOR="#808080">(eval@ e2 x</FONT></I>)</FONT>
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</P>
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<P><FONT FACE="Tms Rmn">will return 7.</FONT><BR>
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</P>
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<P><FONT FACE="Tms Rmn">But if we are not in a lower frame than the one
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x was defined in and write </FONT></P>
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<P><FONT FACE="Tms Rmn"><I><FONT COLOR="#808080">(define e2 (clone-environment
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(current-environment) 1))</FONT></I> </FONT></P>
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<P><FONT FACE="Tms Rmn">and write the value of x is undefined.</FONT> </P>
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<P><FONT FACE="Tms Rmn">(Unless it was defined in the global environment)
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</FONT><BR>
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</P>
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<P><FONT FACE="Tms Rmn">Note: Only the bindings are copied. The bound values
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are not. Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define x (cons 1 2))</FONT></FONT></I>
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</P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define e (clone-environment
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(current-environment))) </FONT></FONT></I></P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(eval@ e (set-cdr! X 6))</FONT></FONT></I>
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</P>
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<P><FONT FACE="Tms Rmn">will change the 2 into 6 at both environments.
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However,</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(set! x 7)</FONT></FONT></I>
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</P>
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<P><FONT FACE="Tms Rmn">will only affect one copy.</FONT><BR>
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</P>
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<CENTER><P><FONT FACE="Tms Rmn"><B><FONT COLOR="#008080">(pop-environment
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env)</FONT></B> </FONT><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Returns the current environment without the first
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frame. This means the first frame on the list of frames is "popped"
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out.</FONT> </P>
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<P><FONT FACE="Tms Rmn">If <B><FONT COLOR="#008080">env</FONT></B> was
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made from f3->f2->f1->Global, the result will be f2->f1->Global.</FONT>
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</P>
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<P><FONT FACE="Tms Rmn">(fx means frame number x)</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define e2 (pop-environment
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(current-environment)))</FONT></FONT></I><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(extend-environment
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env)</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Extends <B><FONT COLOR="#008080">env </FONT></B>with
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a new empty frame (where nothing is defined yet).</FONT> </P>
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<P><FONT FACE="Tms Rmn">This means the if <B><FONT COLOR="#008080">env
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</FONT></B>was f2->f1->Global the result will be f3->f2->f1->Global.</FONT>
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</P>
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<P><FONT FACE="Tms Rmn">(fx means frame number x)</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define e2 (extend-environment
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(current-environment)))</FONT></FONT></I><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(current-environment)
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</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Returns the current environment.</FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(environment?
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env) </FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">A predicate that is true if <B><FONT COLOR="#008080">env
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</FONT></B>is an environment.</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><FONT FACE="Tms Rmn"><I><FONT COLOR="#808080">(environment? (current-environment))</FONT></I>
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</FONT></P>
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<P><FONT FACE="Tms Rmn">Will return true.</FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(parent-environment)
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</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Returns the parent environment. This is the environment
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where <B><FONT COLOR="#008080">(new-thread)</FONT></B> was called to create
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this thread. The First thread returns the global environment.</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(eval@ (parent-environment)
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y)</FONT></FONT></I> </P>
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<P><FONT FACE="Tms Rmn">Will return the value of y in the parent environment.</FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(base-environment)
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</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">The environment where the interpreter runs. </FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(set-base-environment
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env)</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Sets the base environment (where the interpreter
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runs) to be <B><FONT COLOR="#008080">env</FONT></B></FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(set-base-environment
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(parent-environment))</FONT></FONT></I> </P>
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<P><FONT FACE="Tms Rmn">Will make this thread run in the same environment
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as its father)</FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(eval@ env forms...)
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</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Evaluates forms in given environment.</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define x 7)</FONT></FONT></I>
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</P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define e2 (clone-environment
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(current-environment)))</FONT></FONT></I> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(eval@ e2 x)</FONT></FONT></I><BR>
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</P>
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<P><FONT FACE="Tms Rmn">The result will be 7</FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(eval@p forms...)
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</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Evaluates forms in parent environment.</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><FONT FACE="Tms Rmn">Say we want to make our turtle walk 30 degrees
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more than the father's turtle. Then we can write:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(set-heading! T (+ 30
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(eval@p (turtle-heading t))))</FONT></FONT></I><BR>
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</P>
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<H2><A NAME="MESSAGE"></A>MESSAGE QUEUES<BR>
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</H2>
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<P><FONT FACE="Tms Rmn">Message queues are MT-safe mechanisms used to pass
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messages, possibly between threads. Messages accepted must be cons, its
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car being the message type and the cdr is the message body. Both can be
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any kind of Scheme object.</FONT><BR>
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<BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(make-queue)</FONT></FONT></B>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Creates a new message queue.</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define q (make-queue))
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</FONT></FONT></I><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(message-queue?
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q)</FONT></FONT></B> </P></CENTER>
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<P><FONT FACE="Tms Rmn">A predicate that is true if <B><FONT COLOR="#008080">q</FONT></B>
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is a queue.</FONT> </P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(message-queue? q) </FONT></FONT></I></P>
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<P><FONT FACE="Tms Rmn">Will return true for q from the previous example.</FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(peek-message
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q [type])</FONT></FONT></B><BR>
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</P></CENTER>
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<P><FONT FACE="Tms Rmn">Return true if there is a message (of given type,
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or of any type if unspecified) in the queue <B><FONT COLOR="#008080">q</FONT></B>.</FONT>
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</P>
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(peek-message q)</FONT></FONT></I>
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</P>
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<P><FONT FACE="Tms Rmn">Will return falsif the queue q is empty.</FONT>
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</P>
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<P><FONT FACE="Tms Rmn">Note: types are compared using <I><FONT COLOR="#808080">(equals?)</FONT></I>
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.</FONT><BR>
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</P>
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<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(post-message
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q typ_msg)</FONT></FONT></B><BR>
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</P></CENTER>
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|
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<P><FONT FACE="Tms Rmn">Posts the message <B><FONT COLOR="#008080">typ_msg</FONT></B>
|
||
|
|
to the queue <B><FONT COLOR="#008080">q. </FONT></B></FONT></P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><B><FONT COLOR="#008080">typ_msg</FONT></B> must
|
||
|
|
be a cons (type . message).</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(post-message q (cons
|
||
|
|
'type-welcome 'hello))</FONT></FONT><FONT FACE="Miriam"> </FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(get-message [time-out]
|
||
|
|
q [type])</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Get message from queue <B><FONT COLOR="#008080">q
|
||
|
|
, </FONT></B>if <B><FONT COLOR="#008080">time-out </FONT></B>is defined
|
||
|
|
waits only <B><FONT COLOR="#008080">time-out</FONT></B> seconds, and </FONT></P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">optionally gets only messages from type <B><FONT COLOR="#008080">type.</FONT></B></FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define msg (get-message
|
||
|
|
7 q 'type-welcome))</FONT></FONT></I> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">The result will be (if the previous posting was
|
||
|
|
done) ('type-welcome . 'hello)</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Note: types are compared using <I><FONT COLOR="#808080">(equals?)</FONT></I>
|
||
|
|
.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<H2><A NAME="WINDOW"></A>WINDOW COMMANDS<BR>
|
||
|
|
<BR>
|
||
|
|
</H2>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">A window is the graphical board on which the turtles
|
||
|
|
and the user draw. It is a bitmap of size 800x600. </FONT><BR>
|
||
|
|
<BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(new-window [name])
|
||
|
|
</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Makes a new window, <B><FONT COLOR="#008080">name</FONT></B>
|
||
|
|
is a symbol or a string which will also be the window's title. The window's
|
||
|
|
color will be white and it's size 800x600.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define w (new-window
|
||
|
|
'my-window))</FONT></FONT></I> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will create a new window with the title my-window.
|
||
|
|
</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(rename-window!
|
||
|
|
win [name])</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Renames the window win. <B><FONT COLOR="#008080">name</FONT></B>
|
||
|
|
is a symbol or a string which will also be the window's title.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(rename-window! w 'foo)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will make the title of w to be foo.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(set-background-color!
|
||
|
|
R G B)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Set the background color of the window. All the
|
||
|
|
turtles in the window are notified on the new color (used in pen-erase)</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">The colors are defined in terms of <B><FONT COLOR="#008080">R</FONT></B>ed
|
||
|
|
<B><FONT COLOR="#008080">G</FONT></B>reen <B><FONT COLOR="#008080">B</FONT></B>lue
|
||
|
|
(where 0,0,0 is black and 255,255,255 is white).</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(set-background-color!
|
||
|
|
w 255 255 0)</FONT></FONT></I> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will turn the background color of <B><FONT COLOR="#008080">w
|
||
|
|
</FONT></B>to yellow</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(clear-window
|
||
|
|
w) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Clears the screen from all the previous drawings,
|
||
|
|
leaving only the turtles images on it.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(clear-window w)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(load-bitmap w
|
||
|
|
"filename" [x y])</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Loads the bitmap <B><FONT COLOR="#008080">"filename"</FONT></B>
|
||
|
|
and makes it the background of w. <B><FONT COLOR="#008080">x y </FONT></B>are
|
||
|
|
the coordinates of the upper left corner of the picture. If <B><FONT COLOR="#008080">x
|
||
|
|
y </FONT></B>are not given then the picture is centered.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(load-bitmap w "c:\\windows\\forest.bmp")
|
||
|
|
</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">This operation can also be done using the Board
|
||
|
|
menu.</FONT><BR>
|
||
|
|
<BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(save-bitmap w
|
||
|
|
"filename")</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Saves the window into a bitmap file called <B><FONT COLOR="#008080">"filename"</FONT></B>.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(save-bitmap w "my_draw.bmp")
|
||
|
|
</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">This operation can also be done using the Board
|
||
|
|
menu.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><FONT FACE="Tms Rmn"><B><FONT COLOR="#008080">(window-alive?
|
||
|
|
win)</FONT></B> </FONT><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">True if <B><FONT COLOR="#008080">win</FONT></B>
|
||
|
|
is alive, meaning it can get commands.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(window-name w)</FONT></FONT></B>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Returns the name of <B><FONT COLOR="#008080">w</FONT></B>.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(window-name w)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will return "foo" on our window. </FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<H2><A NAME="TURTLE"></A>TURTLE COMMANDS</H2>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">A turtle is an object which is connected to a certain
|
||
|
|
window. It has inner state variables:</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- width</FONT>: the width
|
||
|
|
of the pen.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- heading:</FONT> the direction
|
||
|
|
the turtle will go on command <B><FONT COLOR="#008080">forward!</FONT></B>.
|
||
|
|
The heading is in degrees where 0 is upwards and adding to the heading
|
||
|
|
means clock wise rotation.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- visibility:</FONT> if the
|
||
|
|
body of the turtle is visible on the board or not.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- solid:</FONT> if the turtle
|
||
|
|
is a "solid" turtle (its interior is also drawn) or "hollow"
|
||
|
|
one (only its circumference is drawn).</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- position:</FONT> the location
|
||
|
|
of the turtle on the board, where 0,0 is the upper left corner.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- color:</FONT> the color
|
||
|
|
of the turtle and it's pen, given in RGB format.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- pen condition: </FONT>the
|
||
|
|
turtle's pen can be in three states:</FONT> </P>
|
||
|
|
|
||
|
|
<UL>
|
||
|
|
<LI><FONT FACE="Tms Rmn"><FONT COLOR="#000080">pen-down</FONT> : the turtle
|
||
|
|
will draw as it moves.</FONT> </LI>
|
||
|
|
|
||
|
|
<LI><FONT FACE="Tms Rmn"><FONT COLOR="#000080">pen-up</FONT> : the turtle
|
||
|
|
will not draw as it moves.</FONT> </LI>
|
||
|
|
|
||
|
|
<LI><FONT FACE="Tms Rmn"><FONT COLOR="#000080">pen-erase</FONT> : the turtle
|
||
|
|
will draw in the color of the background as it moves.</FONT> </LI>
|
||
|
|
</UL>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn"><FONT COLOR="#008080">- pen width: </FONT>the width
|
||
|
|
of the pen, the bigger the width the thicker the pen will be.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Turtles can also "see" the board or other
|
||
|
|
turtles (only from the same board) and can handle user interrupts. A turtle
|
||
|
|
is always connected to a certain view, which is the view it is drawing
|
||
|
|
on. Turtles can move between views. </FONT><BR>
|
||
|
|
<BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(make-turtle win
|
||
|
|
[name])</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Creates and return a new turtle, in window win,
|
||
|
|
optional name (where <B><FONT COLOR="#008080">name</FONT></B> can be anything).</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">The inner state of the new turtle will be:</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<UL>
|
||
|
|
<LI><FONT FACE="Tms Rmn">position - 400,300</FONT> </LI>
|
||
|
|
|
||
|
|
<LI><FONT FACE="Tms Rmn">heading - 0</FONT> </LI>
|
||
|
|
|
||
|
|
<LI><FONT FACE="Tms Rmn">color - 0,0,0 (black)</FONT> </LI>
|
||
|
|
|
||
|
|
<LI><FONT FACE="Tms Rmn">width - 2</FONT> </LI>
|
||
|
|
|
||
|
|
<LI><FONT FACE="Tms Rmn">visible - true</FONT> </LI>
|
||
|
|
|
||
|
|
<LI><FONT FACE="Tms Rmn">solid - true</FONT> </LI>
|
||
|
|
</UL>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define t (make-turtle
|
||
|
|
'turty)) </FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-alive?
|
||
|
|
t) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">A predicate that is true if <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
is alive, meaning <B><FONT COLOR="#008080">t </FONT></B>can get commands.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(turtle-alive? t) </FONT></FONT></I></P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will return true on our t.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(clone-turtle
|
||
|
|
t [name])</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Creates an identical turtle to <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
(same inner state).</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define t2 (clone-turtle
|
||
|
|
t))</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(rename-turtle
|
||
|
|
t [name])</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Renames the turtle, name is a string or a symbol</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(rename-turtle t 'pongy)
|
||
|
|
</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-name t)
|
||
|
|
</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Returns the name of <B><FONT COLOR="#008080">t</FONT></B>.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(turtle-name t)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will return "pongy" on our t.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(forward! t d)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Makes <B><FONT COLOR="#008080">t</FONT></B> go
|
||
|
|
forward (in the heading of <B><FONT COLOR="#008080">t</FONT></B>)
|
||
|
|
<B><FONT COLOR="#008080">d</FONT></B> steps.
|
||
|
|
<B><FONT COLOR="#008080">t </FONT></B>will draw while going according to
|
||
|
|
the state of it's pen.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(forward! t 100)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will cause <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
to go forward 100 steps. (In our case since <B><FONT COLOR="#008080">t</FONT></B>'s
|
||
|
|
heading hasn't changed it will go upwards)</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-width!
|
||
|
|
t n)</FONT></FONT></B> </P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Set the width of <B><FONT COLOR="#008080">t</FONT></B>'s
|
||
|
|
pen to be <B><FONT COLOR="#008080">n</FONT></B>. The bigger <B><FONT COLOR="#008080">n</FONT></B>
|
||
|
|
is the wider the pen will be.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(backwards! t
|
||
|
|
d) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Same as forward, just in the opposite direction.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(backwards! t 100)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">is the same as </FONT></P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(forward! t -100)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(right! t d)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will set a new heading to <B><FONT COLOR="#008080">t</FONT></B>.
|
||
|
|
The new heading is the old heading plus <B><FONT COLOR="#008080">d, </FONT></B>meaning
|
||
|
|
<B><FONT COLOR="#008080">t</FONT></B> will rotate clock-wise.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(right! t 90)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will make <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
turn 90 degrees to the </FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(left! t d)</FONT></FONT></B>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Same as right, other direction</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(set-heading!
|
||
|
|
t val)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Sets the heading of <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
to be <B><FONT COLOR="#008080">val. </FONT></B>0 is upwards and 90 is to
|
||
|
|
the right.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(set-heading t 180)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will cause <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
to point to the bottom of the screen.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(move-to! t x
|
||
|
|
y) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Makes <B><FONT COLOR="#008080">t</FONT></B> move
|
||
|
|
to point <B><FONT COLOR="#008080">x,y</FONT></B> without painting. 0,0
|
||
|
|
is the top-left corner of the window.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(move-to! T 100 100)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will cause <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
to move to point 100,100.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(draw-to! t x
|
||
|
|
y) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Moves <B><FONT COLOR="#008080">t</FONT></B> to
|
||
|
|
<B><FONT COLOR="#008080">x,y </FONT></B>possibly drawing or erasing according
|
||
|
|
to the state of <B><FONT COLOR="#008080">t</FONT></B>'s pen.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(draw-to! t 0 0)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(move-turtle-to-window
|
||
|
|
t win)</FONT></FONT></B> </P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Move <B><FONT COLOR="#008080">t</FONT></B> to the
|
||
|
|
window <B><FONT COLOR="#008080">win</FONT></B></FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(move-turtle-to-window
|
||
|
|
t w)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(pen-up! t)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">The pen of <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
is up, so he won't paint when moving.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(pen-up! t)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(pen-down! t)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Causes <B><FONT COLOR="#008080">t</FONT></B>'s
|
||
|
|
pen to be down, meaning he will draw as he is moving.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(pen-erase! t)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Causes <B><FONT COLOR="#008080">t</FONT></B>'s
|
||
|
|
pen to be in the same color as the background color of the window it is
|
||
|
|
attached to.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(show-turtle!
|
||
|
|
t) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Makes <B><FONT COLOR="#008080">t</FONT></B> visible.
|
||
|
|
Meaning he will be seen on the board.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(show-turtle! t)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(hide-turtle!
|
||
|
|
t) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Makes <B><FONT COLOR="#008080">t</FONT></B> invisible.
|
||
|
|
Meaning he will not be seen on the board. (but all the drawing he does
|
||
|
|
will be seen)</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(hide-turtle! t)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(make-turtle-solid!
|
||
|
|
t)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Makes <B><FONT COLOR="#008080">t</FONT></B> a solid
|
||
|
|
turtle.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(make-turtle-hollow!
|
||
|
|
t)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Make <B><FONT COLOR="#008080">t</FONT></B> a "hollow"
|
||
|
|
turtle.</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(kill-turtle!
|
||
|
|
t) </FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Kills <B><FONT COLOR="#008080">t</FONT></B>. Meaning
|
||
|
|
it will be erased from the board and will not accept further commands.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Note: This is the only way to get rid of a turtle.</FONT>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(kill-turtle! t)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will cause when writing <I><FONT COLOR="#808080">t</FONT></I>
|
||
|
|
in the command line to the response</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">#<dead turtle></FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(set-color! t
|
||
|
|
R G B) or (set-color! t (list R G B)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Sets <B><FONT COLOR="#008080">t</FONT></B>'s color
|
||
|
|
(and it's pen), in RGB format.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(set-color! t 255 0 255)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will cause <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
to be pinkish.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Same as:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define pinkish '(255
|
||
|
|
0 255))</FONT></FONT></I> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(set-color! t pinkish)</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-inner-state
|
||
|
|
t)</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Returns a list of 6 parameters: color, heading,
|
||
|
|
hidden-flag, pen width, solid flag, location (cons x y))</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define new-t (make-turtle
|
||
|
|
w))</FONT></FONT></I> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(turtle-inner-state new-t)</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will return the list</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">((0 0 0) 0.0 #f 2 #t (400.0
|
||
|
|
. 300.0))</FONT></FONT></I><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Below are functions that returns only one of the
|
||
|
|
parameters returned by <B><FONT COLOR="#008080">turtle-inner-state</FONT></B>:
|
||
|
|
</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-color t)</FONT></FONT></B>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-heading t)</FONT></FONT></B>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-visible t)</FONT></FONT></B>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-width t)</FONT></FONT></B>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-solid? t)</FONT></FONT></B>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(turtle-position t)</FONT></FONT></B><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<H2><A NAME="VISION"></A>TURTLE VISION<BR>
|
||
|
|
</H2>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">A turtle can interact with the board. It can "see"
|
||
|
|
colors or other turtles.</FONT><BR>
|
||
|
|
<BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(look t distance
|
||
|
|
angle '(R G B))</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will return true if there is a point in color <B><FONT COLOR="#008080">(R
|
||
|
|
G B) </FONT></B>in distance <B><FONT COLOR="#008080">distance </FONT></B>from
|
||
|
|
<B><FONT COLOR="#008080">t</FONT></B> and in the area bordered by the angle
|
||
|
|
2*<B><FONT COLOR="#008080">angle.</FONT></B></FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
|
||
|
|
|
||
|
|
<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(look t 50 20 '(0 0 0))</FONT></FONT></I>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Will cause <B><FONT COLOR="#008080">t</FONT></B>
|
||
|
|
to search for the color black (RGB 0,0,0) in the area shown here in blue:</FONT><BR>
|
||
|
|
</P>
|
||
|
|
|
||
|
|
<CENTER><P><IMG border=0 SRC="img00003.gif" HEIGHT=75 WIDTH=48><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<CENTER><P><B><FONT FACE="Tms Rmn"><FONT COLOR="#008080">(look t distance
|
||
|
|
angle [t1])</FONT></FONT></B><BR>
|
||
|
|
</P></CENTER>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">Same as if looking for color, just this time it
|
||
|
|
will be true is t1 is in the visible area.</FONT> </P>
|
||
|
|
|
||
|
|
<P><FONT FACE="Tms Rmn">If no target turtle is defined then the function
|
||
|
|
will return true if any turtle from this window is in the visible area.</FONT>
|
||
|
|
</P>
|
||
|
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<P><FONT FACE="Tms Rmn">Example:</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(define new-t (clone-turtle
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t))</FONT></FONT></I> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(forward! new-t 30)</FONT></FONT></I>
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</P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(look t 50 20 new-t)</FONT></FONT></I>
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</P>
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<P><FONT FACE="Tms Rmn">And</FONT> </P>
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<P><I><FONT FACE="Tms Rmn"><FONT COLOR="#808080">(look t 50 20)</FONT></FONT></I>
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</P>
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<P><FONT FACE="Tms Rmn">Will both return true.</FONT><BR>
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<BR>
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</P>
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<H2><A NAME="INTERRUPTS"></A>INTERRUPTS (NOTIFICATIONS<TT><FONT FACE="Courier New"><FONT SIZE=+1>)
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</FONT></FONT></TT><BR>
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</H2>
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<P><FONT FACE="Tms Rmn">A turtle can hold a list of interrupts (or notifications).
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When an interrupt is invoked it send a given message to the thread that
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sent the command. Every interrupt is defined by a "look" arguments.
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An interruptcan be of three kinds: </FONT><BR>
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</P>
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<P><FONT FACE="Tms Rmn">A "yes" interrupt - The interrupt will
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happen (message sent) on every "first" time the look returns
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yes.</FONT> </P>
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<P><FONT FACE="Tms Rmn">Meaning if a turtle is told to invoke an interrupt
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every time it sees blue on a certain region. Then the first time it sees
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blue it will invoke the interrupt. From now on if the blue is in view it
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will not invoke the interrupt. Then if it loses sight of the blue object,
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the next time it sees blue again it will invoke the interrupt, and so on.</FONT><BR>
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</P>
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<P><FONT FACE="Tms Rmn">A "no" interrupt - Same as the "yes"
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interrupt, just this time the interrupt is invoked when the sought object
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is not seen.</FONT><BR>
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</P>
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<P><FONT FACE="Tms Rmn">A " |