850 lines
29 KiB
Plaintext
850 lines
29 KiB
Plaintext
* setf
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* plists
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* backquote
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* symbol< (make < generic), generic compare function
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? (cdr nil) should be nil
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* multiple-argument mapcar
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? multi-argument apply. for builtins, just push them. for lambdas, must
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cons together the evaluated arguments.
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? option *print-shared*. if nil, it still handles circular references
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but does not specially print non-circular shared structure
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? option *print-circle*
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* read support for #' for compatibility
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* #\c read character as code (including UTF-8 support!)
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* #| |# block comments
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- here-data for binary serialization. proposed syntax:
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#>size:data, e.g. #>6:000000
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* use syntax environment concept for user-defined macros to plug
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that hole in the semantics
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* make more builtins generic. if typecheck fails, call out to the
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generic version to try supporting more types.
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compare/equal
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+-*/< for all numeric types
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length for all sequences
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? aref/aset for all sequences (vector, list, c-array)
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? copy
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* fixnump, all numeric types should pass numberp
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- make sure all uses of symbols don't assume symbols are unmovable without
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checking ismanaged()
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* eliminate compiler warnings
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* fix printing nan and inf
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- move to "2.5-bit" type tags
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? builtin abs()
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- try adding optional arguments, (lambda (x (opt 0)) ...), see if performance
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is acceptable
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* (syntax-environment) to return it as an assoc list
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* (environment) for variables, constantp
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* prettier printing
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* readable gensyms and #:
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. #:n reads similar to #n=#.(gensym) the first time, and #n# after
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* circular equal
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* integer/truncate function
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? car-circularp, cdr-circularp, circularp
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- hashtable. plan as equal-hash, over three stages:
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1. first support symbol and fixnum keys, use ptrhash. only values get
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relocated on GC.
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2. create a version of ptrhash that uses equal() and hash(). if a key is
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inserted requiring this, switch vtable pointer to use these functions.
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both keys and values get relocated on GC.
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3. write hash() for pairs and vectors. now everything works.
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- expose eq-hashtable to user
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- other backquote optimizations:
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* (nconc x) => x for any x
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. (copy-list (list|append|nconc ...)) => (list|append|nconc ...)
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* (apply vector (list ...)) => (vector ...)
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. (nconc (cons x nil) y) => (cons x y)
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* let form without initializers (let (a b) ...), defaults to nil
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* print (quote a) as 'a, same for ` etc.
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- template keyword arguments. you write
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(template (:test eq) (:key caar)
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(defun assoc (item lst)
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(cond ((atom lst) ())
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((:test (:key lst) item) (car lst))
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(t (assoc item (cdr lst))))))
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This writes assoc as a macro that produces a call to a pre-specialized
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version of the function. For example
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(assoc x l :test equal)
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first tries to look up the variant '(equal caar) in the dictionary for assoc.
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If it doesn't exist it gets generated and stored. The result is a lambda
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expression.
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The macro returns ((lambda (item lst) <code for assoc>) x l).
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We might have to require different syntax for template invocations inside
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template definitions, such as
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((t-instance assoc eq :key) item lst)
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which passes along the same key but always uses eq.
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Alternatively, we could use the keysyms without colons to name the values
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of the template arguments, so the keysyms are always used as markers and
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never appear to have values:
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(template (:test eq) (:key caar)
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(defun assoc? (item lst)
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(cond ((atom lst) ())
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((test (key lst) item) ...
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...
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(assoc x y :test test :key key)
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This would be even easier if the keyword syntax were something like
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(: test eq)
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possible optimizations:
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* delay environment creation. represent environment on the stack as
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alternating symbols/values, or if cons instead of symbol then traverse
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as assoc list. only explicitly cons the whole thing when making a closure
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* cons_reserve(n) interface, guarantees n conses available without gc.
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it could even link them together for you more efficiently
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* assoc builtin
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* special check for constant symbol when evaluating head since that's likely
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* remove the loop from cons_reserve. move all initialization to the loops
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that follow calls to cons_reserve.
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- case of lambda expression in head (as produced by let), can just modify
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env in-place in tail position
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* represent lambda environment as a vector (in lispv)
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x setq builtin (didn't help)
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(- list builtin, to use cons_reserve)
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(- let builtin, to further avoid env consing)
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unconventional interpreter builtins that can be used as a compilation
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target without moving away from s-expressions:
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- (*global* . a) ; special form, don't look in local env first
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- (*local* . 2) ; direct stackframe access
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for internal use:
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* a special version of apply that takes arguments on the stack, to avoid
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consing when implementing "call-with" style primitives like trycatch,
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hashtable-foreach, or the fl_apply API
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- try this environment representation:
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for all kinds of functions (except maybe builtin special forms) push
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all arguments on the stack, either evaluated or not.
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for lambdas, push the lambda list and next-env pointers.
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to capture, save the n+2 pointers to a vector
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. this uses n+2 heap or stack words per environment instead of 2n+1 words
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. argument handling is more uniform which could lead to simplifications,
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and a more efficient apply() entry point
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. disadvantage is looking through the lambda list on every lookup. maybe
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improve by making lambda lists vectors somehow?
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bugs:
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* with the fully recursive (simpler) relocate(), the size of cons chains
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is limited by the process stack size. with the iterative version we can
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have unlimited cdr-deep structures.
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* in #n='e, the case that makes the cons for 'e needs to use label fixup
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* symbol token |.| does not work
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* ltable realloc not multiplying by sizeof(unsigned long)
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* not relocating final cdr in iterative version if it is a vector
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- (setf (car x) y) doesn't return y
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* reader needs to check errno in isnumtok
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* prettyprint size measuring is not utf-8 correct
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femtoLisp3...with symbolic C interface
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c values are builtins with value > N_BUILTINS
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((u_int32_t*)cvalue)[0] & 0x3 must always be 2 to distinguish from vectors
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typedef struct _cvtable_t {
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void (*relocate)(struct _cvalue_t *);
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void (*free)(struct _cvalue_t *);
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void (*print)(struct _cvalue_t *, FILE *);
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} cvtable_t;
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; remember: variable-length data preferred over variable-length arglists
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c type representations:
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symbols void, [u]int[8,16,32,64], float, double, [u]char, [u]short,
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[u]int, [u]long, lispvalue
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(c-function ret-type (argtype ...))
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(array type N)
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(struct ((name type) (name type) ...))
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(union ((name type) (name type) ...))
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(enum (name1 name2 ...))
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(pointer type)
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constructors:
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([u]int[8,16] n)
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([u]int32 hi lo)
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([u]int64 b3 b2 b1 b0)
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(float hi lo) or (float "3.14")
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(double b3 b2 b1 b0) or (double "3.14")
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(array ctype (val ...))
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(struct ((name type) ...) (val ...))
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(pointer cvalue) ; constructs pointer to the given value
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(pointer ctype ptr) ; copies/casts a pointer to a different type
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so (pointer 'int8 #int32(0)) doesn't make sense, but
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(pointer 'int8 (pointer #int32(0))) does.
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(c-function ret-type (argtype ...) ld-symbol-name)
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? struct/enum tag:
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(struct 'tag <initializer>) or (pointer (struct tag))
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where tag is a global var with a value ((name type) ...)
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representing c data from lisp is the tricky part to make really elegant and
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efficient. the most elegant but too inefficient option is not to have opaque
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C values at all and always marshal to/from native lisp values like #int16[10].
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the next option is to have opaque values "sometimes", for example returning
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them from C functions but printing them using their lisp representations.
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the next option is to relax the idea that C values of a certain type have a
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specific lisp structure, and use a coercion system that "tries" to translate
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a lisp value to a specified C type. for example [0 1 2], (0 1 2),
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#string[0 1 2], etc. might all be accepted by a C function taking int8_t*.
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you could say (c-coerce <lispvalue> <typedesc>) and get a cvalue back or
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an error if the conversion fails.
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the final option is to have cvalues be the only officially-sanctioned
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representation of c data, and make them via constructors, like
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(int32 hi lo) returns an int32 cvalue
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(struct '((name type) (name type) ...) a b ...) makes a struct
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there is a constructor function for each primitive C type.
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you can print these by brute force as e.g. #.(int32 hi lo)
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then all checking just looks like functions checking their arguments
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this option seems almost ideal. what's wrong with it?
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. to construct cvalues from lisp you have to build code instead of data
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. it seems like it should take more explicit advantage of tagged vectors
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. should you accept multiple forms? for example
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(array 'int8 0 1 2) or (array 'int8 [0 1 2])
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if you're going to be that permissive, why not allow [0 1 2] to be passed
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directly to a function that expects int8_t* and do the conversion
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implicitly?
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. even if these c-primitive-constructor functions exist, you can still
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write things like c-coerce (in lisp, even) and hack in implicit
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conversion attempts when something other than a cvalue is passed.
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. the printing code is annoying, because it's not enough to print readably,
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you have to print evaluably.
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. solution: constructor notation, #int32(hi lo)
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in any case, "opaque" cvalues will not really be opaque because we want to
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know their types and be able to take them apart on the byte level from lisp.
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C code can get references to lisp values and manipulate them using lisp
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operations like car, so to be fair it should work vice-versa; give
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c references to lisp code and let it use c operations like * on them.
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you can write lisp in c and c in lisp, though of course you don't usually
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want to. however, c written in lisp can be generated by a macro, printed,
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and fed to TCC for compilation.
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for a struct the names and types are parameters of the type, not the
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constructor, so it seems more correct to do
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((struct (name type) (name type) ...) (val val ...))
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where struct returns a constructor. but this isn't practical because it
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can't be printed in constructor notation and the type is a lambda rather
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than a more sensible expression.
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notice constructor calls and type representations are "similar". they
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should be related formally:
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(define (new type)
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(if (symbolp type) (apply (eval type) ())
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(apply (eval (car type)) (cdr type))))
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for aggregate types, you can keep a variable referring to the relevant
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piece:
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(setq point '((x int) (y int)))
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(struct point [2 3]) ; looks like c declaration 'struct point x;'
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a type is a function, so something similar to typedef is achieved by:
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(define (point_t vals) (struct point vals))
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design points:
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. type constructors will all be able to take 1 or 0 arguments, so i could say
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(new (typeof val)) ; construct similar
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(define (new type)
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(if (symbolp type) (apply (eval type) ())
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(apply (eval (car type)) (cdr type))))
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. values can be marked as autorelease (1) if user says so, (2) if we can
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prove that it's ok (e.g. we only allocated the value using malloc because
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it is too large to move on every GC).
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in the future you should be able to specify an arbitrary finalization
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function, not just free().
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. when calling a C function, a value of type_t can be passed to something
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expecting a type_t* by taking the address of the representation. BUT
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this is dangerous if the C function might save a reference.
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a type_t* can be passed as a type_t by copying the representation.
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. you can use (pointer v) to switch v to "malloc'd representation", in
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which case the value is no longer autoreleased, but you can do whatever
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you want with the pointer. (other option is to COPY v when making a
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pointer to it, but this still doesn't prevent C from holding a reference
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too long)
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add a cfunction binding to symbols. you register in C simply by setting
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this binding to a function pointer, then
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(defun open (path flags)
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; could insert type checks here
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(ccall 'int32 'open path flags))
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(setq fd (open "path" 0))
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using libdl you could even omit the registration step and extra binding
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this is possible:
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(defun malloc (size)
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(ccall `(array int8 ,size) 'malloc size))
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;ret type ;f name ; . args
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vtable:
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we'd like to be able to define new lisp "types", like vectors
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and hash tables, using this. there needs to be a standard value interface
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you can implement in C and attach a vtable to some c values.
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interface: relocate, finalize, print(, copy)
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implementation plan:
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- write cvalue constructors
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- if a head evaluates to a cvalue, call the pointer directly with the arg array
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. this is the "guest function" interface, a C function written specifically
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to the femtolisp API. its type must be
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'(c-function lispvalue ((pointer lispvalue) uint32))
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which corresponds to
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value_t func(value_t *args, u_int32_t nargs);
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. this interface is useful for writing additional builtins, types,
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interpreter extensions, etc. more efficient.
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. one of these functions could also be called with
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(defun func args
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(ccall 'func 'lispvalue (array 'lispvalue args) (length args)))
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- these functions are effectively builtins and should have names so they
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can be printed as such.
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. have a registration function
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void guest_function(value_t (*f)(value_t*,u_int32_t), const char *name);
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so at least the function type can be checked from C
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. set a flags bit for functions registered this way so we can identify
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them quickly
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- ccall lisp builtin, (ccall rettype name . args). if name has no cfunc
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binding, looks it up lazily with dlsym and stores the result.
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this is a guest function that handles type checking, translation, and
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invocation of foreign c functions.
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- you could register builtins from lisp like this:
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(defun dlopen (name flags) (ccall '(pointer void) 'dlopen name flags))
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(defun dlsym (handle name type) (ccall type 'dlsym handle name))
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(define lisp-process (dlopen nil 0))
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(define vector-sym
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(dlsym lisp-process 'int_vector
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'(function lispvalue (pointer lispvalue) uint32)))
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(ccall 'void 'guest_function vector-sym 'vector)
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- write c extensions cref, cset, typeof, sizeof, cvaluep
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* read, print, vectorp methods for vectors
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- quoted string "" reading, produces #(c c c c ...)
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* get rid of primitive builtins read,print,princ,load,exit,
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implement using ccall
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other possible design:
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- just add two builtins, call and ccall.
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(call 'name arg arg arg) lisp guest function interface
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we can say e.g.
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(defmacro vector args `(call 'vector ,.args))
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- basically the question is whether to introduce a new kind of callable
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object or to do everything through the existing builtin mechanism
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. macros cannot be applied, so without a new kind of callable 'vector'
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would have to be a lisp function, entailing argument consing...
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(defun builtin (name)
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(guest-function name
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(dlsym lisp-process name '(function value (pointer value) uint32))))
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then you can print a guest function as e.g.
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#.(builtin 'vector)
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#name(x y z) reads as a tagged vector
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#(x y z) is the same as #vector(x y z)
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should be internally the same as well, so non-taggedness does not formally
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exist.
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then we can write the vector clause in backquote as e.g.
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(if (vectorp x)
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(let ((body (bq-process (vector-to-list x))))
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(if (eq (tag x) 'vector)
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(list 'list-to-vector body)
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(list 'apply 'tagged-vector
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(list cons (list quote (tag x)) body))))
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(list quote x))
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setup plan:
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- create source directory and svn repository, move llt sources into it
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* write femtolisp.h, definitions for extensions to #include
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- add fl_ prefix to all exported functions
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- port read and print to jclib's iostreams
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* get rid of flutils; use ptrhash instead
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* builtinp needs to be a builtin ;) to distinguish lisp builtins from cvalues
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* allocation and gc for cvalues
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- interface functions fl_list(...), fl_apply
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e.g. fl_apply(fl_eval(fl_symbol("+")), fl_list(fl_number(2),fl_number(3)))
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and fl_symval("+"), fl_cons, etc.
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-----------------------------------------------------------------------------
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vector todo:
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* compare for vectors
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- (aref v i j k) does (reduce aref v '(i j k)); therefore (aref v) => v
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- (aref v ... [1 2 3] ...) vectorized indexing
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- make (setf (aref v i j k) x) expand to (aset (aref v i j) k x)
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these should be done using the ccall interface:
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- concatenate
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- copy-vec
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- (range i j step) to make integer ranges
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- (rref v start stop), plus make it settable! (rset v start stop rhs)
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lower priority:
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- find (strstr)
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functions to be generic over vec/list:
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* compare, equal, length
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constructor notation:
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#func(a b c) does (apply func '(a b c))
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-----------------------------------------------------------------------------
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how we will allocate cvalues
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a vector's size will be a lisp-value number. we will set bit 0x2 to indicate
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a resize request, and bit 0x1 to indicate that it's actually a cvalue.
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every cvalue will have the following fields, followed by some number of
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words according to how much space is needed:
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value_t size; // | 0x2
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cvtable_t *vtable;
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struct {
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#ifdef BITS64
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unsigned pad:32;
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#endif
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unsigned whatever:27;
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unsigned mark:1;
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unsigned hasparent:1;
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unsigned islispfunction:1;
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unsigned autorelease:1;
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unsigned inlined:1;
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} flags;
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value_t type;
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size_t len; // length of *data in bytes
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//void *data; // present if !inlined
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//value_t parent; // present if hasparent
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size/vtable have the same meaning as vector size/elt[0] for relocation
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obviously we only relocate parent and type. if vtable->relocate is present,
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we call it at the end of the relocate process, and it must touch every
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lisp value reachable from it.
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when a cvalue is created with a finalizer, its address is added to a special
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list. before GC, everything in that list has its mark bit set. when
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we relocate a cvalue, clear the bit. then go through the list to call
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finalizers on dead values. this is O(n+m) where n is amt of live data and m
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is # of values needing finalization. we expect m << heapsize.
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-----------------------------------------------------------------------------
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Goal: bootstrap a lisp system where we can do "anything" purely in lisp
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starting with the minimal builtins needed for successive levels of
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completeness:
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1. Turing completeness
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quote, if, lambda, eq, atom, cons, car, cdr
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2. Naming
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set
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3. Control flow
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progn, prog1, apply, eval
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call/cc needed for true completeness, but we'll have attempt, raise
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4. Predicate completeness
|
|
symbolp, numberp, builtinp
|
|
|
|
5. Syntax
|
|
macro
|
|
|
|
6. I/O completeness
|
|
read, print
|
|
|
|
7. Mutable state
|
|
rplaca, rplacd
|
|
|
|
8. Arithmetic completeness
|
|
+, -, *, /, <
|
|
|
|
9. The missing data structure(s): vector
|
|
alloc, aref, aset, vectorp, length
|
|
|
|
10. Real-world completeness (escape hatch)
|
|
ccall
|
|
|
|
---
|
|
11. Misc unnecessary
|
|
while, label, cond, and, or, not, boundp, vector
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
exception todo:
|
|
|
|
* silence 'in file' errors when user frame active
|
|
* add more useful data to builtin exception types:
|
|
(UnboundError x)
|
|
(BoundsError vec index)
|
|
(TypeError fname expected got)
|
|
(Error v1 v2 v3 ...)
|
|
* attempt/raise, rewrite (error) in lisp
|
|
* more intelligent exception printers in toplevel handler
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
lisp variant ideas
|
|
|
|
- get rid of separate predicates and give every value the same structure
|
|
ala mathematica
|
|
. (tag 'a) => symbol
|
|
(tag '(a b)) => a
|
|
(tag 'symbol 'a) => a
|
|
(tag 'blah 3) => (blah 3)
|
|
- have only vectors, not cons cells (sort of like julia)
|
|
. could have a separate tag field as above
|
|
|
|
- easiest way to add vectors:
|
|
. allocate in same heap with conses, have a tag, size, then elements
|
|
(each elt must be touched on GC for relocation anyway, so might as well
|
|
copy collect it)
|
|
. tag pointers as builtins, we identify them as builtins with big values
|
|
. write (vector) in C, use it from read and eval
|
|
|
|
8889314663 comcast net #
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
cvalues reserves the following global symbols:
|
|
|
|
int8, uint8, int16, uint16, int32, uint32, int64, uint64
|
|
char, uchar, short, ushort, int, uint, long, ulong
|
|
float, double
|
|
struct, array, enum, union, function, void, pointer, lispvalue
|
|
|
|
it defines (but doesn't reserve) the following:
|
|
|
|
typeof, sizeof, autorelease, guestfunction, ccall
|
|
|
|
|
|
user-defined types and typedefs:
|
|
|
|
the rule is that a type should be viewed as a self-evaluating constant
|
|
like a number. if i define a complex_t type of two doubles, then
|
|
'complex_t is not a type any more than the symbol 'x could be added to
|
|
something just because it happened to have the value 2.
|
|
|
|
; typedefs from lisp
|
|
(define wchar_t 'uint32)
|
|
(define complex_t '(struct ((re double) (im double))))
|
|
|
|
; use them
|
|
(new complex_t)
|
|
(new `(array ,complex_t 10))
|
|
(array complex_t 10)
|
|
|
|
BUT
|
|
|
|
(array 'int32 10)
|
|
|
|
because the primitive types *are* symbols. the fact that they have values is
|
|
just a convenient coincidence that lets you do e.g. (int32 0)
|
|
|
|
|
|
; size-annotate a pointer
|
|
(setq p (ccall #c-function((pointer void) (ulong) malloc) n)
|
|
(setq a (deref p `(array int8 ,n)))
|
|
|
|
cvalues todo:
|
|
|
|
- use uint32_t instead of wchar_t in C code
|
|
- make sure empty arrays and 0-byte types really work
|
|
* allow int constructors to accept other int cvalues
|
|
* array constructor should accept any cvalue of the right size
|
|
* make sure cvalues participate well in circular printing
|
|
- lispvalue type
|
|
. keep track of whether a cvalue leads to any lispvalues, so they can
|
|
be automatically relocated (?)
|
|
* float, double
|
|
- struct, union
|
|
- pointer type, function type
|
|
- finalizers and lifetime dependency tracking
|
|
- functions autorelease, guestfunction
|
|
- cref/cset/byteref/byteset
|
|
* wchar type, wide character strings as (array wchar)
|
|
* printing and reading strings
|
|
- ccall
|
|
- anonymous unions
|
|
* fix princ for cvalues
|
|
|
|
- string constructor/concatenator:
|
|
(string 'sym #char(65) #wchar(945) "blah" 23)
|
|
; gives "symA\u03B1blah23"
|
|
"ccc" reads to (array char)
|
|
|
|
low-level functions:
|
|
; these are type/bounds-checked accesses
|
|
- (cref|ccopy cvalue key) ; key is field name or index
|
|
- (cset cvalue key cvalue) ; key is field name, index, or struct offset
|
|
- (get-[u]int[8,16,32,64] cvalue addr)
|
|
; n is a lisp number or cvalue of size <= 8
|
|
- (set-[u]int[8,16,32,64] cvalue addr n)
|
|
- (c-struct-offset type field)
|
|
- (c2lisp cvalue) ; convert to sexpr form
|
|
- (autorelease cvalue) ; mark cvalue as free-on-gc
|
|
* (typeof cvalue)
|
|
* (sizeof cvalue|type)
|
|
- (deref pointer[, type]) ; convert an unknown pointer to a safe cvalue
|
|
- (ccopy cv)
|
|
|
|
; (sizeof '(pointer type)) == sizeof(void*)
|
|
; (sizeof '(array type N)) == N * sizeof(type)
|
|
|
|
|
|
things you can do with cvalues:
|
|
|
|
. call native C functions from lisp code without wrappers
|
|
. wrap C functions in pure lisp, automatically inheriting some degree
|
|
of type safety
|
|
. use lisp functions as callbacks from C code
|
|
. use the lisp garbage collector to reclaim malloc'd storage
|
|
. annotate C pointers with size information for bounds checking
|
|
. attach symbolic type information to a C data structure, allowing it to
|
|
inherit lisp services such as printing a readable representation
|
|
. add datatypes like strings to lisp
|
|
. use more efficient represenations for your lisp programs' data
|
|
|
|
|
|
family of cvalue representations.
|
|
relevant attributes:
|
|
. large -- needs full size_t to represent size
|
|
. inline -- allocated along with metadata
|
|
. prim -- no stored type; uses primtype bits in flags
|
|
. hasdeps -- depends on other values to stay alive
|
|
|
|
these attributes have the following dependencies:
|
|
. large -> !inline
|
|
. prim -> !hasdeps && !large
|
|
|
|
so we have the following possibilities:
|
|
|
|
large inline prim hasdeps rep#
|
|
0 0 0 0 0
|
|
0 0 0 1 1
|
|
|
|
0 0 1 0 2
|
|
0 1 0 0 3
|
|
0 1 0 1 4
|
|
0 1 1 0 5
|
|
|
|
1 0 0 0 6
|
|
1 0 0 1 7
|
|
|
|
we need to be able to un-inline data, so we need:
|
|
change 3 -> 0 (easy; write pointer over data)
|
|
change 4 -> 1
|
|
change 5 -> 2 (also easy)
|
|
|
|
|
|
rep#0&1: (!large && !inline && !prim)
|
|
typedef struct {
|
|
cvflags_t flags;
|
|
value_t type;
|
|
value_t deps;
|
|
void *data; /* points to malloc'd buffer */
|
|
} cvalue_t;
|
|
|
|
rep#3&4: (!large && inline && !prim)
|
|
typedef struct {
|
|
cvflags_t flags;
|
|
value_t type;
|
|
value_t deps;
|
|
/* data goes here inlined */
|
|
} cvalue_t;
|
|
|
|
|
|
rep#2: (prim && !inline)
|
|
typedef struct {
|
|
cvflags_t flags;
|
|
void *data; /* points to (tiny!) malloc'd buffer */
|
|
} cvalue_t;
|
|
|
|
rep#5: (prim && inline)
|
|
typedef struct {
|
|
cvflags_t flags;
|
|
/* data goes here inlined */
|
|
} cvalue_t;
|
|
|
|
|
|
rep#6&7: (large)
|
|
typedef struct {
|
|
cvflags_t flags;
|
|
value_t type;
|
|
value_t deps;
|
|
void *data; /* points to malloc'd buffer */
|
|
size_t len;
|
|
} cvalue_t;
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
times for lispv:
|
|
|
|
color 2.286s
|
|
sort 0.181s
|
|
fib34 5.205s
|
|
mexpa 0.329s
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
finalization algorithm that allows finalizers written in lisp:
|
|
|
|
right after GC, go through finalization list (a weak list) and find objects
|
|
that didn't move. relocate them (bring them back to life) and push them
|
|
all onto the stack. remove all from finalization list.
|
|
|
|
call finalizer for each value.
|
|
|
|
optional: after calling a finalizer, make sure the object didn't get put
|
|
back on the finalization list, remove if it did.
|
|
if you don't do this, you can make an unkillable object by registering a
|
|
finalizer that re-registers itself. this could be considered a feature though.
|
|
|
|
pop dead values off stack.
|
|
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
femtolisp semantics
|
|
|
|
eval* is an internal procedure of 2 arguments, expr and env, invoked
|
|
implicitly on input.
|
|
The user-visible procedure eval performs eval* e Env ()
|
|
|
|
eval* Symbol s E => lookup* s E
|
|
eval* Atom a E => a
|
|
... special forms ... quote arg, if a b c, other symbols from syntax env.
|
|
eval* Cons f args E =>
|
|
|
|
First the head expression, f, is evaluated, yielding f-.
|
|
Then control is passed to #.apply f- args
|
|
#.apply is the user-visible apply procedure.
|
|
(here we imagine there is a user-invisible environment where f- is
|
|
bound to the value of the car and args is bound to the cdr of the input)
|
|
|
|
|
|
Now (apply b lst) where b is a procedure (i.e. satisfies functionp) is
|
|
identical to
|
|
(eval (map (lambda (e) `',e) (cons b lst)))
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
design of new toplevel
|
|
|
|
system.lsp is compiled into the executable, and contains definitions of
|
|
(load) and (repl).
|
|
|
|
start with load bound to bootstrap_load (in C)
|
|
on startup we call load on system, then call it again afterwards
|
|
|
|
(load) reads and evaluates every form, keeping track of defined functions
|
|
and macros (at the top level), and grabs a (main ...) form if it sees
|
|
one. it applies optimizations to every definition, then invokes main.
|
|
|
|
an error E during load should rethrow `(load-error ,filename ,E)
|
|
such exceptions can be printed recursively
|
|
|
|
lerror() should make a lisp string S from the result of sprintf, then
|
|
raise `(,e ,S). first argument e should be a symbol.
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
String API
|
|
|
|
*string - append/construct
|
|
string.inc - (string.inc s i [nchars])
|
|
string.dec
|
|
string.char - char at byte offset
|
|
string.count - # of chars between 2 byte offsets
|
|
*string.sub - substring between 2 byte offsets
|
|
*string.split - (string.split s sep-chars)
|
|
string.trim - (string.trim s chars-at-start chars-at-end)
|
|
*string.reverse
|
|
string.find - (string.find s str|char), or nil if not found
|
|
string.map - (string.map f s)
|
|
*string.encode - to utf8
|
|
*string.decode - from utf8 to UCS
|
|
string.width - # columns
|
|
|
|
|
|
IOStream API
|
|
|
|
read
|
|
print, sprint
|
|
princ, sprinc
|
|
stream - (stream cvalue-as-bytestream)
|
|
file
|
|
fifo
|
|
socket
|
|
stream.eof
|
|
stream.write - (stream.write cvalue)
|
|
stream.read - (stream.read ctype)
|
|
stream.copy - (stream.copy to from [nbytes])
|
|
stream.copyuntil - (stream.copy to from byte)
|
|
stream.flush
|
|
stream.pos
|
|
stream.seek
|
|
stream.trunc
|
|
stream.getc - get utf8 character(s)
|
|
|
|
|
|
path.combine
|
|
path.parts
|
|
path.absolute
|
|
path.simplify
|
|
path.tempdir
|
|
path.tempname
|
|
path.homedir
|
|
*path.cwd
|
|
|
|
|
|
*time.now
|
|
time.parts
|
|
time.fromparts
|
|
*time.string
|
|
time.fromstring
|
|
|
|
|
|
*os.name
|
|
*os.getenv
|
|
*os.setenv
|
|
os.execv
|
|
|
|
|
|
*rand
|
|
*rand.uint32
|
|
*rand.uint64
|
|
*rand.double
|
|
|
|
-----------------------------------------------------------------------------
|
|
|
|
prettyprint notes
|
|
|
|
* if head of list causes VPOS to increase and HPOS is a bit large, then
|
|
switch to miser mode, otherwise default is ok, for example:
|
|
|
|
> '((lambda (x y) (if (< x y) x y)) (a b c) (d e f) 2 3 (r t y))
|
|
((lambda (x y)
|
|
(if (< x y) x y)) (a b c)
|
|
(d e f) 2 3
|
|
(r t y))
|
|
|
|
* (if a b c) should always put newlines before b and c
|
|
|
|
* write try_predict_len that gives a length for easy cases like
|
|
symbols, else -1. use it to avoid wrapping symbols around lines
|