92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
/*
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* m a c r o s . c -- Simple statically scoped macros
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*
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* Copyright © 1993-1999 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
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*
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*
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* Permission to use, copy, modify, distribute,and license this
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* software and its documentation for any purpose is hereby granted,
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* provided that existing copyright notices are retained in all
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* copies and that this notice is included verbatim in any
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* distributions. No written agreement, license, or royalty fee is
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* required for any of the authorized uses.
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* This software is provided ``AS IS'' without express or implied
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* warranty.
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*
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* Author: Erick Gallesio [eg@unice.fr]
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* Creation date: ??-Oct-1993 ??:??
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* Last file update: 3-Sep-1999 20:21 (eg)
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*
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*/
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#include "stk.h"
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PRIMITIVE STk_macro(SCM args, SCM env, int len)
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{
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SCM z, code;
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if (len != 2) Err("macro: Bad definition", args);
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code = Cons(Sym_lambda, args); /* Create code before to avoid GC problems */
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NEWCELL(z, tc_macro);
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z->storage_as.macro.code = EVAL(code);
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z->storage_as.macro.env = Ntruth;
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return z;
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}
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PRIMITIVE STk_macro_R5(SCM args, SCM env, int len)
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{
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SCM z = STk_macro(args, env, len);
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z->storage_as.macro.env = env;
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return z;
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}
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/*
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* macro_expand and macro_expand_1 are defined as fsubr rather than subr_1.
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* This provision permits to carry the environment with the form to expand
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* (this permits to corerctly expanse macros which are not are global level,
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* since we do a varlookup instead of grabbing the macro in a global var).
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* But are there people which define macros at a level which are not global?
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*
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*/
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static SCM expand(SCM form, SCM env, int just_1)
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{
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if (CONSP(form)) {
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register SCM tmp, car = CAR(form);
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if (SYMBOLP(car) && MACROP(tmp = *STk_varlookup(car, env, FALSE))) {
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tmp = Apply(tmp->storage_as.macro.code, form);
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return just_1 ? tmp : expand(tmp, env, FALSE);
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}
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}
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return form;
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}
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PRIMITIVE STk_macro_expand_1(SCM form, SCM env, int len)
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{
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if (len != 1) Err("macro-expand-1: bad number of parameters", form);
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return expand(EVAL(CAR(form)), env, TRUE);
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}
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PRIMITIVE STk_macro_expand(SCM form, SCM env, int len)
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{
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if (len != 1) Err("macro-expand: bad number of parameters", form);
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return expand(EVAL(CAR(form)), env, FALSE);
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}
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PRIMITIVE STk_macro_body(SCM form)
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{
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if (NMACROP(form)) Err("macro-body: bad macro", form);
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return Cons(Intern("macro"), CDR(form->storage_as.macro.code));
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}
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PRIMITIVE STk_macrop(SCM obj)
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{
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return MACROP(obj)? Truth: Ntruth;
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}
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