shithub: rgbds

Info  •  Files  •  Log  •  Branches

Eliminate `isAtEOF` by changing `yylex` control flow

`yylex` calls `yywrap` at the beginning of the next call, after it
has set `lexerState->lastToken` to `T_EOB`.

--- a/src/asm/lexer.c

+++ b/src/asm/lexer.c

@@ -354,7 +354,6 @@

 	uint32_t colNo;

 	int lastToken;

 	int nextToken;

-	bool isAtEOF;

 	struct IfStack *ifStack;

@@ -379,7 +378,6 @@

 	state->atLineStart = true; /* yylex() will init colNo due to this */

 	state->lastToken = T_EOF;

 	state->nextToken = 0;

-	state->isAtEOF = false;

 	state->ifStack = NULL;

@@ -571,7 +569,7 @@

 	// that lexer states lifetimes are always properly managed, since they're handled solely

 	// by the fstack... with *one* exception.

 	// Assume a context is pushed on top of the fstack, and the corresponding lexer state gets

-	// scheduled at EOF; `lexerStateAtEOL` thus becomes a (weak) ref to that lexer state...

+	// scheduled at EOF; `lexerStateEOL` thus becomes a (weak) ref to that lexer state...

 	// It has been possible, due to a bug, that the corresponding fstack context gets popped

 	// before EOL, deleting the associated state... but it would still be switched to at EOL.

 	// This assertion checks that this doesn't happen again.

@@ -2280,13 +2278,17 @@

 int yylex(void)

 {

-	if (lexerStateEOL) {

+	if (lexerState->atLineStart && lexerStateEOL) {

 		lexer_SetState(lexerStateEOL);

 		lexerStateEOL = NULL;

 	}

 	/* `lexer_SetState` updates `lexerState`, so check for EOF after it */

-	if (lexerState->isAtEOF)

-		return T_EOF;

+	if (lexerState->lastToken == T_EOB) {

+		if (yywrap()) {

+			dbgPrint("Reached end of input.\n");

+			return T_EOF;

+		}

+	}

 	if (lexerState->atLineStart) {

 		/* Newlines read within an expansion should not increase the line count */

 		if (!lexerState->expansions)

@@ -2303,16 +2305,10 @@

 	int token = lexerModeFuncs[lexerState->mode]();

 	if (token == T_EOF) {

-		/* Try to switch to new buffer; if it succeeds, scan again */

 		dbgPrint("Reached EOB!\n");

 		/* Captures end at their buffer's boundary no matter what */

-		if (!lexerState->capturing) {

-			if (yywrap()) {

-				dbgPrint("Reached end of input.\n");

-				lexerState->isAtEOF = true;

-			}

+		if (!lexerState->capturing)

 			token = T_EOB;

-		}

 	}

 	lexerState->lastToken = token;

 	lexerState->atLineStart = token == T_NEWLINE || token == T_EOB;