take care of escaped characters in string

include/picrin.h

@@ -66,6 +66,7 @@ bool pic_eq_p(pic_state *, pic_value, pic_value);
 
 pic_value pic_intern_cstr(pic_state *, const char *);
 
+pic_value pic_str_new(pic_state *, const char *, size_t);
 pic_value pic_str_new_cstr(pic_state *, const char *);
 
 bool pic_parse(pic_state *, const char *, pic_value *);

src/port.c

@@ -7,6 +7,7 @@
 #include "picrin/string.h"
 
 static void write_pair(pic_state *pic, struct pic_pair *pair);
+static void write_str(pic_state *pic, struct pic_string *str);
 
 static void
 write(pic_state *pic, pic_value obj)
@@ -42,7 +43,9 @@ write(pic_state *pic, pic_value obj)
     printf("#<port %p>", pic_port_ptr(obj));
     break;
   case PIC_TT_STRING:
-    printf("\"%s\"", pic_str_ptr(obj)->str);
+    printf("\"");
+    write_str(pic, pic_str_ptr(obj));
+    printf("\"");
     break;
   }
 }
@@ -64,6 +67,20 @@ write_pair(pic_state *pic, struct pic_pair *pair)
   write(pic, pair->cdr);
 }
 
+static void
+write_str(pic_state *pic, struct pic_string *str)
+{
+  int i;
+  const char *cstr = str->str;
+
+  for (i = 0; i < str->len; ++i) {
+    if (cstr[i] == '"' || cstr[i] == '\\') {
+      putchar('\\');
+    }
+    putchar(cstr[i]);
+  }
+}
+
 void
 pic_debug(pic_state *pic, pic_value obj)
 {

src/scan.l

@@ -11,7 +11,7 @@ struct parser_control {
   bool incomp;
 };
 
-static pic_value escape_string(pic_state *, const char *);
+static pic_value new_escaped_string(pic_state *, const char *);
 
 #define YY_DECL int yylex (struct parser_control *p)
 %}
@@ -47,7 +47,7 @@ string_elem	[^\"\\]|"\\\""|"\\\\"
 {real} 		{ yylval.datum = pic_float_value(atof(yytext)); return tNUMBER; }
 {identifier}	{ yylval.datum = pic_intern_cstr(p->pic, yytext); return tSYMBOL; }
 {string}	{
-		  yylval.datum = escape_string(p->pic, yytext);
+		  yylval.datum = new_escaped_string(p->pic, yytext);
 		  return tSTRING;
 		}
 
@@ -60,19 +60,24 @@ yywrap()
 }
 
 static pic_value
-escape_string(pic_state *pic, const char *str)
+new_escaped_string(pic_state *pic, const char *str)
 {
   size_t len;
   char *new_str;
-  int i;
+  int i,j;
   pic_value v;
 
   len = strlen(str);
   new_str = (char *)pic_alloc(pic, len + 1);
-  for (i = 1; i < len - 1; ++i) {
+  for (j = 0, i = 1; i < len - 1; ++i, ++j) {
-    new_str[i-1] = str[i];
+    if (str[i] == '\\') {
+      ++i;
+      new_str[j] = str[i];
+      continue;
+    }
+    new_str[j] = str[i];
   }
-  new_str[i] = '\0';
+  new_str[j] = '\0';
 
   v = pic_str_new_cstr(pic, new_str);
   pic_free(pic, new_str);

src/string.c

@@ -4,15 +4,14 @@
 #include "picrin/string.h"
 
 pic_value
-pic_str_new_cstr(pic_state *pic, const char *cstr)
+pic_str_new(pic_state *pic, const char *cstr, size_t len)
 {
   struct pic_string *str;
-  size_t len;
   char *new_str;
 
-  len = strlen(cstr);
   new_str = (char *)pic_alloc(pic, len + 1);
-  strncpy(new_str, cstr, len + 1);
+  strncpy(new_str, cstr, len);
+  new_str[len] = '\0';
 
   str = (struct pic_string *)pic_obj_alloc(pic, sizeof(struct pic_string), PIC_TT_STRING);
   str->len = len;
@@ -20,3 +19,12 @@ pic_str_new_cstr(pic_state *pic, const char *cstr)
 
   return pic_obj_value(str);
 }
+
+pic_value
+pic_str_new_cstr(pic_state *pic, const char *cstr)
+{
+  size_t len;
+
+  len = strlen(cstr);
+  return pic_str_new(pic, cstr, len);
+}