Weave of Formal Thought

תקציר מקורי באנגליתarXiv:2606.25987v2 Announce Type: replace Abstract: Large language models attain remarkable surface fluency on code, yet they do not formally guarantee the syntactic validity of their output, nor do they typically leverage the hierarchical structure that defines the target language. While existing constrained-decoding frameworks offer a solution to the former, they predominantly operate under rigid assumptions that preclude critical lexical mechanisms relied upon by modern parsers (e.g., Pythonic indentation). In this work, we present a formal engine and constrained decoder that is sound and complete with respect to the full Tree-sitter specification by augmenting generalized LR (GLR) parsing with a novel speculative-lexing construction that maintains concurrent lexer-state hypotheses sync