*.[ch]: make a distinction between SCM as a generic
[bpt/guile.git] / libguile / macros.c
1 /* Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
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41
42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
43 gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
44
45 \f
46
47 #include "_scm.h"
48 #include "smob.h"
49
50 #include "validate.h"
51 #include "macros.h"
52
53 long scm_tc16_macro;
54
55 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
56 (SCM code),
57 "Returns a @dfn{macro} which, when a symbol defined to this value\n"
58 "appears as the first symbol in an expression, returns the result\n"
59 "of applying @var{code} to the expression and the environment.")
60 #define FUNC_NAME s_scm_makacro
61 {
62 SCM_VALIDATE_PROC (1,code);
63 SCM_RETURN_NEWSMOB (scm_tc16_macro, code);
64 }
65 #undef FUNC_NAME
66
67
68 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
69 (SCM code),
70 "Returns a @dfn{macro} which, when a symbol defined to this value\n"
71 "appears as the first symbol in an expression, evaluates the result\n"
72 "of applying @var{code} to the expression and the environment.\n"
73 "The value returned from @var{code} which has been passed to\n"
74 "@code{procedure->memoizing-macro} replaces the form passed to\n"
75 "@var{code}. For example:\n\n"
76 "@example\n"
77 "(define trace\n"
78 " (procedure->macro\n"
79 " (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
80 "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
81 "@end example\n")
82 #define FUNC_NAME s_scm_makmacro
83 {
84 SCM_VALIDATE_PROC (1,code);
85 SCM_RETURN_NEWSMOB (scm_tc16_macro | (1L << 16), code);
86 }
87 #undef FUNC_NAME
88
89
90 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
91 (SCM code),
92 "Returns a @dfn{macro} which, when a symbol defined to this value\n"
93 "appears as the first symbol in an expression, evaluates the result\n"
94 "of applying @var{proc} to the expression and the environment.\n"
95 "The value returned from @var{proc} which has been passed to\n"
96 "@code{procedure->memoizing-macro} replaces the form passed to\n"
97 "@var{proc}. For example:\n\n"
98 "@example\n"
99 "(define trace\n"
100 " (procedure->macro\n"
101 " (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
102 "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
103 "@end example\n")
104 #define FUNC_NAME s_scm_makmmacro
105 {
106 SCM_VALIDATE_PROC (1,code);
107 SCM_RETURN_NEWSMOB (scm_tc16_macro | (2L << 16), code);
108 }
109 #undef FUNC_NAME
110
111
112 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
113 (SCM obj),
114 "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro or a\n"
115 "syntax transformer.")
116 #define FUNC_NAME s_scm_macro_p
117 {
118 return SCM_BOOL(SCM_NIMP (obj) && SCM_TYP16 (obj) == scm_tc16_macro);
119 }
120 #undef FUNC_NAME
121
122
123 SCM_SYMBOL (scm_sym_syntax, "syntax");
124 SCM_SYMBOL (scm_sym_macro, "macro");
125 SCM_SYMBOL (scm_sym_mmacro, "macro!");
126
127 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
128 (SCM m),
129 "Return one of the symbols @code{syntax}, @code{macro} or @code{macro!},\n"
130 "depending on whether @var{obj} is a syntax tranformer, a regular macro,\n"
131 "or a memoizing macro, respectively. If @var{obj} is not a macro,\n"
132 "@code{#f} is returned.")
133 #define FUNC_NAME s_scm_macro_type
134 {
135 if (!(SCM_NIMP (m) && SCM_TYP16 (m) == scm_tc16_macro))
136 return SCM_BOOL_F;
137 switch ((int) (SCM_CARW (m) >> 16))
138 {
139 case 0: return scm_sym_syntax;
140 case 1: return scm_sym_macro;
141 case 2: return scm_sym_mmacro;
142 default: scm_wrong_type_arg (FUNC_NAME, 1, m);
143 }
144 }
145 #undef FUNC_NAME
146
147
148 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
149 (SCM m),
150 "")
151 #define FUNC_NAME s_scm_macro_name
152 {
153 SCM_VALIDATE_SMOB (1,m,macro);
154 return scm_procedure_name (SCM_CDR (m));
155 }
156 #undef FUNC_NAME
157
158
159 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
160 (SCM m),
161 "")
162 #define FUNC_NAME s_scm_macro_transformer
163 {
164 SCM_VALIDATE_SMOB (1,m,macro);
165 return SCM_CLOSUREP (SCM_CDR (m)) ? SCM_CDR (m) : SCM_BOOL_F;
166 }
167 #undef FUNC_NAME
168
169 SCM
170 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
171 {
172 SCM symcell = scm_sysintern (name, SCM_UNDEFINED);
173 SCM transformer = scm_make_subr_opt (name, scm_tc7_subr_2, fcn, 0);
174 SCM_SETCDR (symcell, macroizer (transformer));
175 return SCM_CAR (symcell);
176 }
177
178 void
179 scm_init_macros ()
180 {
181 scm_tc16_macro = scm_make_smob_type_mfpe ("macro", 0,
182 scm_markcdr, NULL, NULL, NULL);
183 #include "macros.x"
184 }