ELPI(1)

💖 ELPI(1) — User Commands 💖

okay bestie, welcome to the elpi page, aka the embeddable lambda-Prolog interpreter. she's giving language-implementation realness and we're gonna go through everything, no skipping, no cap. 🦋

✨ NAME ✨

elpi — embeddable lambda-Prolog interpreter. that's the whole vibe. she interprets, she embeds, she slays. 💅

✨ SYNOPSIS ✨

elpi [OPTION].. [FILE].. [-- ARGS..]

like, options first, then files, then -- and then whatever args you wanna yeet at her. 🌸

✨ DESCRIPTION ✨

💜 Main options:

• -test — runs the query "main". just straight up runs main, that's it, that's the girl. ✨
• -exec pred — runs the query "pred ARGS". so you hand her a predicate and she runs it with ARGS. iconic.
• -D var — Define variable. this is the conditional compilation one, iykyk. 🎀
• -document-builtins — Print documentation for built-in predicates. free docs, we love that for us. 📚
• -no-tc — don't typecheck the program. living dangerously, I see. 😭
• -delay-problems-outside-pattern-fragment — deprecated, for Teyjus compatibility. it's giving legacy era, bestie. still works, still counts. 💀
• -version — prints the version of Elpi. she'll tell you who she is. 💖

🧚 Parsing options:

• -I PATH — search for accumulated files in PATH. so when stuff gets accumulated, this is where she looks. 🌈

🔥 Tracing options:

• -trace-at FNAME START STOP — print trace between call START and STOP of function FNAME (FNAME can be omitted, default is run). so it's a lil window of trace, very targeted. 👑
• -trace-on KIND FILE — enable trace printing. KIND is tty or json (default is tty). FILE is stdout or stderr (default) or host:port or /path or ./path. yes she can send it over the network, she's flexible like that. 💅
• -trace-skip REX — ignore trace items matching REX. not interested, blocked. 🙈
• -trace-only REX — trace only items matching REX. the opposite energy, obsessed with exactly this. ✨
• -trace-only-pred REX — trace only when the current predicate matches REX. predicate-specific attention, main character energy. 🎀
• -trace-tty-maxbox NUM — Format max_boxes set to NUM. literally just sets max_boxes to NUM. 🫶
• -trace-tty-maxcols NUM — Format margin set to NUM. sets margin to NUM, no notes. 🌸
• -stats-on — Collect statistics. numbers girlies rise. 📊
• -perf-on — Disable trace output, but keep perf. so: no trace noise, all the perf data. best of both. 🔥

Tracing options can be used to debug your programs and the Elpi interpreter. fr fr, that's what they're for.

Tracing points for the user are prefixed with 'user:' while the ones for the Elpi developer with 'dev:'. so you can tell who's talking. 🦋

A sensible set of options to debug your programs is:

-trace-on -trace-at 1 9999 -trace-only '\(run\|select\|user:\)'

copy that, paste that, thank me later. 💖

💀 Debug options (for debugging Elpi, not your program):

bestie, read the parenthetical. these are for debugging Elpi herself, not your cute lil program. don't come for me when you use them and get confused. 😭

• -print-accumulated-files — prints files loaded via accumulate. the receipts of what got accumulated. 🧾
• -print-ast — prints files as parsed, then exit. right after parsing, nothing more. ✨
• -print — prints files after most compilation passes, then exit. she's been through some things at this point. 💅
• -print-passes — prints intermediate data during compilation, then exit. all the messy in-between stages. 🌈
• -print-units — prints compilation units data, then exit. unit by unit, very thorough. 👑

and that's the whole page, bestie!! 💜 every flag, every arg, every default, all present and accounted for. now go trace something and have the best day. mwah! 🎀✨

— signing off: elpi 1.13.7, October 2021, that's the version and the date, love u bye!! 🦋💖