reader supports quasiquote abbrev

include/picrin.h

@@ -27,6 +27,7 @@ typedef struct {
   pic_callinfo *cibase, *ciend;
 
   pic_value sDEFINE, sLAMBDA, sIF, sBEGIN, sQUOTE;
+  pic_value sQUASIQUOTE, sUNQUOTE, sUNQUOTE_SPLICING;
   pic_value sCONS, sCAR, sCDR, sNILP;
   pic_value sADD, sSUB, sMUL, sDIV;
 

src/gc.c

@@ -214,6 +214,9 @@ gc_mark_phase(pic_state *pic)
   gc_mark(pic, pic->sIF);
   gc_mark(pic, pic->sBEGIN);
   gc_mark(pic, pic->sQUOTE);
+  gc_mark(pic, pic->sQUASIQUOTE);
+  gc_mark(pic, pic->sUNQUOTE);
+  gc_mark(pic, pic->sUNQUOTE_SPLICING);
   gc_mark(pic, pic->sCONS);
   gc_mark(pic, pic->sCAR);
   gc_mark(pic, pic->sCDR);

src/pair.c

@@ -1,3 +1,5 @@
+#include <stdarg.h>
+
 #include "picrin.h"
 #include "picrin/pair.h"
 
@@ -48,6 +50,23 @@ pic_list_p(pic_state *pic, pic_value obj)
   return pic_nil_p(obj);
 }
 
+pic_value
+pic_list(pic_state *pic, size_t c, ...)
+{
+  va_list ap;
+  pic_value v;
+
+  va_start(ap, c);
+
+  v = pic_nil_value();
+  while (c--) {
+    v = pic_cons(pic, va_arg(ap, pic_value), v);
+  }
+
+  va_end(ap);
+  return pic_reverse(pic, v);
+}
+
 pic_value
 pic_reverse(pic_state *pic, pic_value list)
 {

src/parse.y

@@ -34,7 +34,7 @@ void yylex_destroy();
 }
 
 %token tLPAREN tRPAREN tDOT
-%token tQUOTE
+%token tQUOTE tQUASIQUOTE tUNQUOTE tUNQUOTE_SPLICING
 %token <datum> tSYMBOL tNUMBER tBOOLEAN tSTRING
 
 %type <datum> datum simple_datum compound_datum abbrev
@@ -43,11 +43,7 @@ void yylex_destroy();
 %%
 
 program
-	:
+	: datum
-	{
-	  p->value = pic_undef_value();
-	}
-	| datum
 	{
 	  p->value = $1;
 	}
@@ -100,24 +96,41 @@ list_data
 abbrev
 	: tQUOTE datum
 	{
-	  $$ = pic_cons(p->pic, p->pic->sQUOTE, pic_cons(p->pic, $2, pic_nil_value()));
+	  $$ = pic_list(p->pic, 2, p->pic->sQUOTE, $2);
+	}
+	| tQUASIQUOTE datum
+	{
+	  $$ = pic_list(p->pic, 2, p->pic->sQUASIQUOTE, $2);
+	}
+	| tUNQUOTE datum
+	{
+	  $$ = pic_list(p->pic, 2, p->pic->sUNQUOTE, $2);
+	}
+	| tUNQUOTE_SPLICING datum
+	{
+	  $$ = pic_list(p->pic, 2, p->pic->sUNQUOTE_SPLICING, $2);
 	}
 ;
 
 incomplete_datum
-	: tLPAREN incomplete_data
+	: /* none */
-	| tQUOTE
+	| tLPAREN incomplete_data
-	| tQUOTE incomplete_datum
+	| incomplete_abbrev
 ;
 
 incomplete_data
-	:  /* none */
+	: incomplete_datum
-	| datum tDOT
-	| datum incomplete_datum
 	| datum tDOT incomplete_datum
 	| datum incomplete_data
 ;
 
+incomplete_abbrev
+	: tQUOTE incomplete_datum
+	| tQUASIQUOTE incomplete_datum
+	| tUNQUOTE incomplete_datum
+	| tUNQUOTE_SPLICING incomplete_datum
+;
+
 %%
 
 void

src/scan.l

@@ -26,7 +26,7 @@ static pic_value new_escaped_string(pic_state *, const char *);
 boolean		#t|#f|#true|#false
 
   /* symbol */
-identifier	[a-z0-9A-Z+-/*!$%&:@^~?<=>_.]+
+identifier	[a-z0-9A-Z+/*!$%&:@^~?<=>_.-]+
 
   /* number */
 digit		[0-9]
@@ -46,6 +46,9 @@ string_elem	[^\"\\]|"\\\""|"\\\\"
 "("		return tLPAREN;
 ")"		return tRPAREN;
 "'"		return tQUOTE;
+"`"		return tQUASIQUOTE;
+","		return tUNQUOTE;
+",@"		return tUNQUOTE_SPLICING;
 {boolean}	{ yylvalp->datum = pic_bool_value(strcmp(yytext, "#t") == 0 || strcmp(yytext, "#true") == 0); return tBOOLEAN; }
 {real} 		{ yylvalp->datum = pic_float_value(atof(yytext)); return tNUMBER; }
 {identifier}	{ yylvalp->datum = pic_intern_cstr(p->pic, yytext); return tSYMBOL; }

src/state.c

@@ -80,6 +80,9 @@ pic_open(int argc, char *argv[], char **envp)
   pic->sIF = pic_intern_cstr(pic, "if");
   pic->sBEGIN = pic_intern_cstr(pic, "begin");
   pic->sQUOTE = pic_intern_cstr(pic, "quote");
+  pic->sQUASIQUOTE = pic_intern_cstr(pic, "quasiquote");
+  pic->sUNQUOTE = pic_intern_cstr(pic, "unquote");
+  pic->sUNQUOTE_SPLICING = pic_intern_cstr(pic, "unquote-splicing");
   pic->sCONS = pic_intern_cstr(pic, "cons");
   pic->sCAR = pic_intern_cstr(pic, "car");
   pic->sCDR = pic_intern_cstr(pic, "cdr");