iris

commit 60d4c2eb9824194b7c1b4a4dda537080f6e6ad25
parent 8dc3257f1cd68efd60176c8d7a51dec9cbae1e40
Author: sin <sin@2f30.org>
Date:   Fri,  9 May 2014 20:52:07 +0100

Use internal state variable to track the lexer's state

Diffstat:
M
lexer.c
 | 
49
++++++++++++++++++++++++++-----------------------

1 file changed, 26 insertions(+), 23 deletions(-)
diff --git a/lexer.c b/lexer.c
@@ -58,7 +58,6 @@ struct tok
 gettok(struct lexerctx *ctx, const char *buf, size_t len)
 {
 	struct tok tok;
-	enum state state = State_Se;
 	char *tmp;
 
 	if (ctx->ready == 0) {
@@ -66,36 +65,36 @@ gettok(struct lexerctx *ctx, const char *buf, size_t len)
 		ctx->e = buf;
 		ctx->ready = 1;
 	}
-
+	ctx->state = State_Se;
 	while (ctx->e < &buf[len]) {
-		switch (state) {
+		switch (ctx->state) {
 		case State_Se:
 			if (*ctx->e == ' ' || *ctx->e == '\t' ||
 			    *ctx->e == '\n')
 				break;
 			if (isalpha(*ctx->e) != 0)
-				state = State_Identifier;
+				ctx->state = State_Identifier;
 			else if (*ctx->e == '#')
-				state = State_Probable_Boolean;
+				ctx->state = State_Probable_Boolean;
 			else if (isdigit(*ctx->e) != 0)
-				state = State_Number;
+				ctx->state = State_Number;
 			else if (*ctx->e == '-' || *ctx->e == '+')
-				state = State_Signed_Number;
+				ctx->state = State_Signed_Number;
 			else if (*ctx->e == '"')
-				state = State_Probable_String;
+				ctx->state = State_Probable_String;
 			else if (*ctx->e == '(')
-				state = State_Lparen;
+				ctx->state = State_Lparen;
 			else if (*ctx->e == ')')
-				state = State_Rparen;
+				ctx->state = State_Rparen;
 			else if (*ctx->e == '\'')
-				state = State_Quote;
+				ctx->state = State_Quote;
 			else if (*ctx->e == '.')
-				state = State_Dot;
+				ctx->state = State_Dot;
 			else if (*ctx->e == ';')
-				state = State_Comment;
+				ctx->state = State_Comment;
 			else
-				state = State_Illegal_Input;
-			if (state != State_Se)
+				ctx->state = State_Illegal_Input;
+			if (ctx->state != State_Se)
 				ctx->s = ctx->e;
 			break;
 		case State_Identifier:
@@ -114,9 +113,9 @@ gettok(struct lexerctx *ctx, const char *buf, size_t len)
 			break;
 		case State_Probable_Boolean:
 			if (*ctx->e == 'f' || *ctx->e == 't')
-				state = State_Boolean;
+				ctx->state = State_Boolean;
 			else if (*ctx->e == '\\')
-				state = State_Probable_Character;
+				ctx->state = State_Probable_Character;
 			else {
 				tok.type = Error;
 				tok.s = "not a boolean or a character";
@@ -156,11 +155,11 @@ gettok(struct lexerctx *ctx, const char *buf, size_t len)
 				tok.e = NULL;
 				return tok;
 			}
-			state = State_Number;
+			ctx->state = State_Number;
 			break;
 		case State_Probable_Character:
 			if (isalpha(*ctx->e) != 0) {
-				state = State_Character;
+				ctx->state = State_Character;
 			} else {
 				tok.type = Error;
 				tok.s = "expected character constant";
@@ -182,7 +181,7 @@ gettok(struct lexerctx *ctx, const char *buf, size_t len)
 			break;
 		case State_Probable_String:
 			if (*ctx->e == '"')
-				state = String;
+				ctx->state = String;
 			break;
 		case State_String:
 			tok.type = String;
@@ -212,7 +211,7 @@ gettok(struct lexerctx *ctx, const char *buf, size_t len)
 		case State_Comment:
 			tmp = strchr(ctx->s, '\n');
 			if (tmp) {
-				state = State_Se;
+				ctx->state = State_Se;
 				ctx->s = tmp;
 			}
 			break;
@@ -229,7 +228,6 @@ gettok(struct lexerctx *ctx, const char *buf, size_t len)
 		}
 		ctx->e++;
 	}
-
 	tok.type = Eof;
 	tok.s = "reached the end-of-file";
 	tok.e = NULL;
@@ -241,9 +239,13 @@ initlexer(void)
 {
 	struct lexerctx *ctx;
 
-	ctx = calloc(1, sizeof(*ctx));
+	ctx = malloc(sizeof(*ctx));
 	if (!ctx)
 		return NULL;
+	ctx->state = State_Se;
+	ctx->ready = 0;
+	ctx->s = NULL;
+	ctx->e = NULL;
 	return ctx;
 }
 
@@ -251,4 +253,5 @@ void
 resetlexer(struct lexerctx *ctx)
 {
 	ctx->ready = 0;
+	ctx->state = State_Se;
 }