andrew/akbasic
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fix five defects the port uncovered in the reference parser and scanner

Browse Source 
Chained subtraction and exponentiation fold left instead of abandoning the
rest of the line -- `1 - 2 - 3` gave -1 and dropped the `- 3`. A unary leaf's
operand moves to .left, so a negative literal is one argument again and a
second argument no longer overwrites it. An operator in a line's final column
survives. Hex literals reach the parser whole. A leading zero is padding, not
a radix.

Item 16 stays pinned: the fix works and costs an upstream golden case, which
is a decision rather than a defect.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Andrew Kesterson
2026-07-31 11:35:14 -04:00
parent f24201fdef
commit 1eb8f9ffaa
14 changed files with 272 additions and 167 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
src/scanner.c
View File

@@ -103,6 +103,15 @@ static bool match_next_char(akbasic_Runtime *obj, char cm, akbasic_TokenType tru
char nc = '\0';
if ( !peek(obj, &nc) ) {
/*
* Nothing left to peek at, so the operator is whatever it is on its
* own. The reference returns here *without* setting a type
* (basicscanner.go:272), which silently drops a comparison operator in
* the final column of a line: `A# =` produced one token, not two, and
* the parse error that followed pointed somewhere else entirely.
* TODO.md section 6 item 14.
*/
obj->tokentype = falsetype;
return false;
}
if ( nc == cm ) {
@@ -144,6 +153,7 @@ static akerr_ErrorContext *match_number(akbasic_Runtime *obj)
char nc = '\0';
int64_t lineno = 0;
long long converted = 0;
bool hex = false;
obj->tokentype = AKBASIC_TOK_LITERAL_INT;
while ( !is_at_end(obj) ) {
@@ -156,8 +166,27 @@ static akerr_ErrorContext *match_number(akbasic_Runtime *obj)
SUCCEED_RETURN(errctx);
}
obj->tokentype = AKBASIC_TOK_LITERAL_FLOAT;
} else if ( !isdigit((unsigned char)c) && c != 'x' ) {
/* 'x' is allowed through so 0x-prefixed hex reaches the parser. */
} else if ( c == 'x' && !hex ) {
/*
* An 'x' in a number run. The reference lets it through and then
* stops at the first hex digit after it (basicscanner.go:318), so
* `0xff` lexed as `0x` followed by an identifier `ff`, the parser's
* base-16 branch was unreachable, and the README's hex support did
* not exist. TODO.md section 6 item 15. Once the 'x' is seen, keep
* going over hex digits.
*
* Accepted anywhere in the run rather than only after a leading `0`,
* which is the reference's rule and is worth keeping: it is what
* makes `1x2` one malformed token that the line-number conversion
* then diagnoses by name, instead of two tokens that fail somewhere
* less helpful.
*/
hex = true;
} else if ( hex ) {
if ( !isxdigit((unsigned char)c) ) {
break;
}
} else if ( !isdigit((unsigned char)c) ) {
break;
}
obj->current += 1;
@@ -231,6 +260,12 @@ static akerr_ErrorContext *match_identifier(akbasic_Runtime *obj)
}
PASS(errctx, get_lexeme(obj, lexeme, sizeof(lexeme)));
/*
* Searched with the type suffix still attached, which is the reference's
* rule (basicscanner.go:349) and is why the "Reserved word in variable name"
* branch below is unreachable -- TODO.md section 6 item 16, which explains
* why it is still here rather than fixed.
*/
PASS(errctx, akbasic_verb_lookup(lexeme, &verb));
ATTEMPT {