diff options
Diffstat (limited to 'module/ice-9/eval.scm')
-rw-r--r-- | module/ice-9/eval.scm | 137 |
1 files changed, 74 insertions, 63 deletions
diff --git a/module/ice-9/eval.scm b/module/ice-9/eval.scm index 4054bd853..554c88e56 100644 --- a/module/ice-9/eval.scm +++ b/module/ice-9/eval.scm @@ -1,6 +1,6 @@ ;;; -*- mode: scheme; coding: utf-8; -*- -;;;; Copyright (C) 2009, 2010, 2012 Free Software Foundation, Inc. +;;;; Copyright (C) 2009, 2010, 2012, 2013 Free Software Foundation, Inc. ;;;; ;;;; This library is free software; you can redistribute it and/or ;;;; modify it under the terms of the GNU Lesser General Public @@ -298,72 +298,83 @@ (1- nopt) args (cdr inits)) (lp (cons (car args) env) (1- nopt) (cdr args) (cdr inits))))) - ;; With keywords, we stop binding optionals at the first - ;; keyword. (let lp ((env env) (nopt* nopt) (args args) (inits inits)) - (if (> nopt* 0) - (if (or (null? args) (keyword? (car args))) - (lp (cons (eval (car inits) env) env) - (1- nopt*) args (cdr inits)) - (lp (cons (car args) env) - (1- nopt*) (cdr args) (cdr inits))) - ;; Finished with optionals. - (let* ((aok (car kw)) - (kw (cdr kw)) - (kw-base (+ nopt nreq (if rest? 1 0))) - (imax (let lp ((imax (1- kw-base)) (kw kw)) - (if (null? kw) - imax - (lp (max (cdar kw) imax) - (cdr kw))))) - ;; Fill in kwargs with "undefined" vals. - (env (let lp ((i kw-base) - ;; Also, here we bind the rest - ;; arg, if any. - (env (if rest? (cons args env) env))) - (if (<= i imax) - (lp (1+ i) (cons unbound-arg env)) - env)))) - ;; Now scan args for keywords. - (let lp ((args args)) - (if (and (pair? args) (pair? (cdr args)) - (keyword? (car args))) - (let ((kw-pair (assq (car args) kw)) - (v (cadr args))) - (if kw-pair - ;; Found a known keyword; set its value. - (list-set! env (- imax (cdr kw-pair)) v) - ;; Unknown keyword. - (if (not aok) - (scm-error 'keyword-argument-error - "eval" "Unrecognized keyword" - '() #f))) - (lp (cddr args))) - (if (pair? args) - (if rest? - ;; Be lenient parsing rest args. - (lp (cdr args)) - (scm-error 'keyword-argument-error - "eval" "Invalid keyword" - '() #f)) - ;; Finished parsing keywords. Fill in - ;; uninitialized kwargs by evalling init - ;; expressions in their appropriate - ;; environment. - (let lp ((i (- imax kw-base)) - (inits inits)) - (if (pair? inits) - (let ((tail (list-tail env i))) - (if (eq? (car tail) unbound-arg) - (set-car! tail - (eval (car inits) - (cdr tail)))) - (lp (1- i) (cdr inits))) - ;; Finally, eval the body. - (eval body env))))))))))))))) + (cond + ;; With keywords, we stop binding optionals at the + ;; first keyword. + ((> nopt* 0) + (if (or (null? args) (keyword? (car args))) + (lp (cons (eval (car inits) env) env) + (1- nopt*) args (cdr inits)) + (lp (cons (car args) env) + (1- nopt*) (cdr args) (cdr inits)))) + ;; Finished with optionals. + ((and alt (pair? args) (not (keyword? (car args))) + (not rest?)) + ;; Too many positional args, no #:rest arg, + ;; and we have an alternate. + (apply alt-proc %args)) + (else + (let* ((aok (car kw)) + (kw (cdr kw)) + (kw-base (+ nopt nreq (if rest? 1 0))) + (imax (let lp ((imax (1- kw-base)) (kw kw)) + (if (null? kw) + imax + (lp (max (cdar kw) imax) + (cdr kw))))) + ;; Fill in kwargs with "undefined" vals. + (env (let lp ((i kw-base) + ;; Also, here we bind the rest + ;; arg, if any. + (env (if rest? + (cons args env) + env))) + (if (<= i imax) + (lp (1+ i) (cons unbound-arg env)) + env)))) + ;; Now scan args for keywords. + (let lp ((args args)) + (if (and (pair? args) (pair? (cdr args)) + (keyword? (car args))) + (let ((kw-pair (assq (car args) kw)) + (v (cadr args))) + (if kw-pair + ;; Found a known keyword; set its value. + (list-set! env + (- imax (cdr kw-pair)) v) + ;; Unknown keyword. + (if (not aok) + (scm-error + 'keyword-argument-error + "eval" "Unrecognized keyword" + '() #f))) + (lp (cddr args))) + (if (pair? args) + (if rest? + ;; Be lenient parsing rest args. + (lp (cdr args)) + (scm-error 'keyword-argument-error + "eval" "Invalid keyword" + '() #f)) + ;; Finished parsing keywords. Fill in + ;; uninitialized kwargs by evalling init + ;; expressions in their appropriate + ;; environment. + (let lp ((i (- imax kw-base)) + (inits inits)) + (if (pair? inits) + (let ((tail (list-tail env i))) + (if (eq? (car tail) unbound-arg) + (set-car! tail + (eval (car inits) + (cdr tail)))) + (lp (1- i) (cdr inits))) + ;; Finally, eval the body. + (eval body env)))))))))))))))) ;; The "engine". EXP is a memoized expression. (define (eval exp env) |