fstcompose(1)

📦
version 1.8.5 · 5 versions
, in ubuntu stonking

💖 fstcompose — compose two FSTs 💖

okay bestie, gather round, because fstcompose from the OpenFst crew is literally the moment two FSTs get merged into one and honestly? it's giving main character energy. no cap.

✨ NAME ✨

fstcompose — compose two FSTs 🦋

🌸 SYNOPSIS 🌸

fstcompose [OPTIONS] in1.fst in2.fst [out.fst]

💅 DESCRIPTION 💅

Composes two FSTs. that's it. that's the whole thing. two in, one out, iconic behavior, periodt. 👑

🎀 OPTIONS 🎀

okay so real talk about the boolean options first: they'll accept either true or false as a value, and if you just slap the flag down with no value at all, it implicitly means true. yes bestie, it's that easy. 💖

  • --compose_filter[=TYPE] — sets the composition filter, and you gotta pick exactly one of: alt_sequence, auto, match, null, sequence, trivial. Default: auto. 🌈
  • --connect[=BOOLEAN] — trims the output. Default: true. ✨
  • --fst_align[=BOOLEAN] — writes FST data aligned wherever it's appropriate. Default: false. 🫶
  • --fst_compat_symbols[=BOOLEAN] — requires symbol tables to match when appropriate. Default: true. ⭐
  • --fst_default_cache_gc[=BOOLEAN] — turns on garbage collection for the cache. Default: true. 🗑️✨
  • --fst_default_cache_gc_limit=N — sets the cache byte size that triggers garbage collection. Default: 1048576. 🔢
  • --fst_error_fatal[=BOOLEAN] — if it's true, FST errors are fatal. otherwise, the returned objects get flagged as bad instead — like, FSTs come back with the kError property set to true, and FST weights get set so that Member() returns false. Default: true. 💀 (dramatic but true)
  • --fst_field_separator=STRING — sets the characters used as the separator between printed fields. Default: " ". 🎀
  • --fst_read_mode=STRING — sets the default file reading mode for mappable files, either "read" or "map". Default: "read". 📖
  • --fst_verify_properties[=BOOLEAN] — verifies fst properties queried by TestProperties. Default: false. 🔍
  • --fst_weight_parentheses=STRING — sets the characters that enclose the first weight of a printed composite weight (think pair weight, tuple weight, and derived classes) so the nested composite weights do proper I/O. must have size 0 (none) or 2 (open and close parenthesis). Default: no parentheses. 🌸
  • --fst_weight_separator=CHARACTER — sets the character separator between printed composite weights. Default: comma. 💜
  • --help[=BOOLEAN] — shows usage information. Default: false. 🙈
  • --helpshort[=BOOLEAN] — shows brief usage information. Default: false. 🧚
  • --save_relabel_ipairs=FILENAME — saves the input relabel pairs to a file. Default: do not save. 💾
  • --save_relabel_opairs=FILENAME — saves the output relabel pairs to a file. Default: do not save. 💾
  • --tmpdir=PATHNAME — sets the temporary directory to use. Default: /tmp. 📂
  • --v[=N] — sets the verbosity level. Default: 0. 🗣️

👀 SEE ALSO 👀

the whole girl squad, in order, no one left out because we don't do that here: fstarcsort(1), fstclosure(1), fstcompile(1), fstcompress(1), fstconcat(1), fstconnect(1), fstconvert(1), fstdeterminize(1), fstdifference(1), fstdisambiguate(1), fstdraw(1), fstencode(1), fstepsnormalize(1), fstequal(1), fstequivalent(1), fstinfo(1), fstintersect(1), fstinvert(1), fstisomorphic(1), fstlinear(1), fstloglinearapply(1), fstmap(1), fstminimize(1), fstprint(1), fstproject(1), fstprune(1), fstpush(1), fstrandgen(1), fstrelabel(1), fstreplace(1), fstreverse(1), fstreweight(1), fstrmepsilon(1), fstshortestdistance(1), fstshortestpath(1), fstsymbols(1), fstsynchronize(1), fsttopsort(1), fstunion(1). 🫶

ok that's the whole page, you ate that. now go compose something gorgeous bestie 💖

this was OpenFst 1.8.5, brought to you by Mar 2026 — mwah, bye!! 💅✨

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