Resolve some TODO comments

- `out_PushSection` should not set `currentSection` to NULL because
  PUSHS, PUSHC, and PUSHO consistently keep the current section,
  charmap, and options, even though the stack has been pushed.

- `Callback__FILE__` does not need to assert that `fileName` is not
  empty because `__FILE__`'s value is quoted, and can safely be empty.

- `YY_FATAL_ERROR` and `YYLMAX` are not needed since the lexer is
  not generated with flex.

src/asm/fstack.c

@@ -417,7 +417,7 @@ void fstk_RunMacro(char const *macroName, struct MacroArgs *args)
 	memcpy(dest, macro->name, macroNameLen + 1);
 
 	newContext((struct FileStackNode *)fileInfo);
-	contextStack->lexerState = lexer_OpenFileView(macro->macro, macro->macroSize,
+	contextStack->lexerState = lexer_OpenFileView("MACRO", macro->macro, macro->macroSize,
 						      macro->fileLine);
 	if (!contextStack->lexerState)
 		fatalerror("Failed to set up lexer for macro invocation\n");
@@ -451,7 +451,7 @@ static bool newReptContext(int32_t reptLineNo, char *body, size_t size)
 	/* Correct our line number, which currently points to the `ENDR` line */
 	contextStack->fileInfo->lineNo = reptLineNo;
 
-	contextStack->lexerState = lexer_OpenFileView(body, size, reptLineNo);
+	contextStack->lexerState = lexer_OpenFileView("REPT", body, size, reptLineNo);
 	if (!contextStack->lexerState)
 		fatalerror("Failed to set up lexer for REPT block\n");
 	lexer_SetStateAtEOL(contextStack->lexerState);

src/asm/lexer.c

@@ -304,6 +304,8 @@ static bool isWhitespace(int c)
 }
 
 #define LEXER_BUF_SIZE 42 /* TODO: determine a sane value for this */
+/* The buffer needs to be large enough for the maximum `peekInternal` lookahead distance */
+static_assert(LEXER_BUF_SIZE > 1, "Lexer buffer size is too small");
 /* This caps the size of buffer reads, and according to POSIX, passing more than SSIZE_MAX is UB */
 static_assert(LEXER_BUF_SIZE <= SSIZE_MAX, "Lexer buffer size is too large");
 
@@ -531,7 +533,7 @@ struct LexerState *lexer_OpenFile(char const *path)
 	return state;
 }
 
-struct LexerState *lexer_OpenFileView(char *buf, size_t size, uint32_t lineNo)
+struct LexerState *lexer_OpenFileView(char const *path, char *buf, size_t size, uint32_t lineNo)
 {
 	dbgPrint("Opening view on buffer \"%.*s\"[...]\n", size < 16 ? (int)size : 16, buf);
 
@@ -541,8 +543,8 @@ struct LexerState *lexer_OpenFileView(char *buf, size_t size, uint32_t lineNo)
 		error("Failed to allocate memory for lexer state: %s\n", strerror(errno));
 		return NULL;
 	}
-	// TODO: init `path`
 
+	state->path = path; /* Used to report read errors in `peekInternal` */
 	state->isFile = false;
 	state->isMmapped = true; /* It's not *really* mmap()ed, but it behaves the same */
 	state->ptr = buf;

src/asm/section.c

@@ -902,7 +902,6 @@ void out_PushSection(void)
 	sect->offset = curOffset;
 	sect->next = sectionStack;
 	sectionStack = sect;
-	/* TODO: maybe set current section to NULL? */
 }
 
 void out_PopSection(void)

src/asm/symbol.c

@@ -96,8 +96,6 @@ static char const *Callback__FILE__(void)
 	char const *fileName = fstk_GetFileName();
 	size_t j = 1;
 
-	/* TODO: is there a way for a file name to be empty? */
-	assert(fileName[0]);
 	/* The assertion above ensures the loop runs at least once */
 	for (size_t i = 0; fileName[i]; i++, j++) {
 		/* Account for the extra backslash inserted below */
@@ -175,7 +173,7 @@ static void updateSymbolFilename(struct Symbol *sym)
 	/* If the old node was referenced, ensure the new one is */
 	if (oldSrc && oldSrc->referenced && oldSrc->ID != (uint32_t)-1)
 		out_RegisterNode(sym->src);
-	/* TODO: unref the old node, and use `out_ReplaceNode` instead if deleting it */
+	/* TODO: unref the old node, and use `out_ReplaceNode` instead of deleting it */
 }
 
 /*
@@ -226,7 +224,6 @@ static void assignStringSymbol(struct Symbol *sym, char const *value)
 		fatalerror("No memory for string equate: %s\n", strerror(errno));
 
 	sym->type = SYM_EQUS;
-	/* TODO: use other fields */
 	sym->macro = string;
 	sym->macroSize = strlen(string);
 }

src/asm/warning.c

@@ -152,8 +152,7 @@ void processWarningFlag(char const *flag)
 				errx(1, "Cannot make meta warning \"%s\" into an error",
 				     flag);
 
-			uint8_t const *ptr =
-					metaWarningCommands[id - NB_WARNINGS];
+			uint8_t const *ptr = metaWarningCommands[id - NB_WARNINGS];
 
 			for (;;) {
 				if (*ptr == META_WARNING_DONE)
@@ -194,7 +193,7 @@ void processWarningFlag(char const *flag)
 	bool isNegation = !strncmp(flag, "no-", strlen("no-")) && !setError;
 	char const *rootFlag = isNegation ? flag + strlen("no-") : flag;
 	enum WarningState state = setError ? WARNING_ERROR :
-			isNegation ? WARNING_DISABLED : WARNING_ENABLED;
+				  isNegation ? WARNING_DISABLED : WARNING_ENABLED;
 
 	/* Try to match the flag against a "normal" flag */
 	for (enum WarningID id = 0; id < NB_WARNINGS; id++) {