diff options
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | eval.c | 42 | ||||
| -rw-r--r-- | txr.1 | 40 |
3 files changed, 90 insertions, 0 deletions
@@ -1,5 +1,13 @@ 2014-02-20 Kaz Kylheku <kaz@kylheku.com> + * eval.c (macro_form_p, macroexpand_1, macroexpand): New static + functions. + (eval_init): Registered new functions. + + * txr.1: Documented. + +2014-02-20 Kaz Kylheku <kaz@kylheku.com> + * parser.y (unquotes_occur): Bugfix: we should not terminate the recursion early if we see a quote. This would be true if the only quotes were those generated by the parser based on @@ -2209,6 +2209,43 @@ tail: } } +static val macro_form_p(val form) +{ + if (!consp(form)) + return nil; + if (!gethash(top_mb, car(form))) + return nil; + return t; +} + +static val macroexpand_1(val form, val mac_env) +{ + val macro; + + mac_env = default_arg(mac_env, make_env(nil, nil, nil)); + + if (atom(form)) { + return form; + } else if ((macro = gethash(top_mb, car(form)))) { + val mac_expand = expand_macro(form, macro, mac_env); + if (mac_expand == form) + return form; + rlcp_tree(mac_expand, form); + return mac_expand; + } + return form; +} + +static val macroexpand(val form, val mac_env) +{ + for (;;) { + val mac_expand = macroexpand_1(form, mac_env); + if (mac_expand == form) + return form; + form = mac_expand; + } +} + val mapcarv(val fun, val list_of_lists) { if (!cdr(list_of_lists)) { @@ -2895,6 +2932,11 @@ void eval_init(void) reg_fun(intern(lit("lisp-parse"), user_package), func_n2o(lisp_parse, 0)); reg_fun(intern(lit("read"), user_package), func_n2o(lisp_parse, 0)); reg_fun(intern(lit("expand"), system_package), func_n1(expand)); + reg_fun(intern(lit("macro-form-p"), user_package), func_n1(macro_form_p)); + reg_fun(intern(lit("macroexpand-1"), user_package), + func_n2o(macroexpand_1, 1)); + reg_fun(intern(lit("macroexpand"), user_package), + func_n2o(macroexpand, 1)); reg_fun(intern(lit("chain"), user_package), func_n0v(chainv)); reg_fun(intern(lit("andf"), user_package), func_n0v(andv)); reg_fun(intern(lit("orf"), user_package), func_n0v(orv)); @@ -12736,6 +12736,46 @@ Examples: (let ((,var (car i))) ,*body)))) +.SS Function macro-form-p + +.TP +Syntax: + + (macro-form-p <obj>) + +.TP +Description: + +The macro-form-p function returns t if <obj> represents the syntax of +a form which is a macro form. Otherwise it returns nil. + +A macro form will transform under macroexpand-1 or macroexpand; an object +which isn't a macro form will not undergo expansion. + +.SS Functions macroexpand-1 and macroexpand + +.TP +Syntax: + + (macroexpand-1 <obj>) + (macroexpand <obj>) + +.TP +Description: + +If <obj> is a macro form (an object for which macro-form-p returns t), +these functions expand the macro form and return the expanded form. +Otherwise, they return <obj>. + +macroexpand-1 performs a single expansion, expanding just the macro +that is referenced by the symbol in the first position of <obj>, +and returns the expansion. That expansion may itself be a macro form. + +macroexpand performs an expansion, like macroexpand-1. If the result is +a macro form, then it expands that form, and keeps repeating this process +until the expansion yields a non-macro-form. That non-macro-form is then +returned. + .SS Operator tree-bind .TP |