add backslash escape sequences to string literals

2 files changed, 32 insertions, 7 deletions

diff --git a/mem.h b/mem.h
index 84fa4bb..87f817b 100644
--- a/mem.h
+++ b/mem.h
@@ -15,12 +15,12 @@ void *M(State *S, void *ptr, size_t old, size_t new);
 
 // needs len,cap,d fields
 #define ENSURE_CAP(S, darr, type, needed) \
-	if (darr.cap < needed) { \
+	do { if (darr.cap < needed) { \
 		size_t __newsz = next_pwrof2(needed); \
 	    if (__newsz < 8) __newsz = 8; \
 		darr.d = RENEW_ARR(S, darr.d, type, darr.cap, __newsz); \
 	    darr.cap = __newsz; \
-	}
+	} } while (0)
 
 size_t next_pwrof2(size_t x);
 
diff --git a/read.c b/read.c
index 5b3f43e..26dcfd5 100644
--- a/read.c
+++ b/read.c
@@ -1,4 +1,5 @@
 #include "val.h"
+#include "mem.h"
 #include "util.h"
 
 #include <string.h>
@@ -87,12 +88,36 @@ static Val symbol(Reader *R) {
 	}
 }
 static Val string(Reader *R) {
-	char *start = R->c;
-	int len = 0;
-	// todo, escape sequences
-	while (*R->c != '"') { len += 1; next(R); }
+	struct {
+		size_t len;
+		size_t cap;
+		char *d;
+	} str;
+	str.len = 0;
+	str.cap = 0;
+	str.d = NULL;
+
+	#define append(c) do { ENSURE_CAP(R->S, str, char, str.cap+1); str.d[str.len++] = c; } while (0)
+	
+	while (*R->c != '"') { 
+		if (*R->c == '\\') {
+			next(R);
+			switch (*R->c) {
+			case '\\': append('\\'); break;
+			case 't': append('\t'); break;
+			case 'n': append('\n'); break;
+			case '"': append('"'); break;
+			}
+			next(R);
+		} else {
+			append(*R->c);
+			next(R);
+		}
+	}
+	append('\0');
+	#undef append
 	next(R);
-	ObjString *s = objstring_copy(R->S, start, len);
+	ObjString *s = objstring_take(R->S, str.d, str.len-1);
 	return en(R, "quote", VAL_OBJ(s));
 }
 static Val list(Reader *R, char closer) {