Fix invalid [|] parsing when | is operator #3206
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When | is defined as an operator (e.g., via dcgs), expressions like 1*[|] incorrectly parsed because the | was treated as a term due to its operator spec. This caused compute_arity_in_list() to steal terms from before the [ bracket. The fix explicitly rejects HeadTailSeparator at term positions in compute_arity_in_list(), since [|...] with nothing before | is always invalid regardless of whether | is an operator. Fixes: #5
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Summary
[|]inside expressions like1*[|]incorrectly parsed when|is defined as an operator (e.g., vialibrary(dcgs))|with XFY spec was being treated as a term incompute_arity_in_list(), causing it to steal terms from before the[bracketBug Report
jjtolton#5
Test Cases
All should throw
syntax_errorwhen|is operator (1105 xfy):"{1*[|]. }." % space before } "{ ! * [ | ] * ! }." % spaces throughout "{!*[|]*!}." % no spaces "!*[|]*!." % without braces "(!*[|]*!)." % with parens "!*[|]*1." % ending with number "!*[|]*A." % ending with variableFix
Explicitly reject
HeadTailSeparatorat term positions incompute_arity_in_list(), since[|...]with nothing before|is always invalid.