stdlib: finish the String module - #47
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Eight members, the smallest of the sweeps because String was already the best-covered module. isEmpty takes the name every other container uses. get is the one worth arguing about: it answers Option and is bounds-checked, exactly like List.get, and since there is no char type a character comes back as a one-character string. Before this, reading one character meant slice i (i + 1), which is total but says nothing about what it is for. The rest: repeat, trimStart and trimEnd (strip already did both ends), splitLines, rev, and ofList as the inverse of toList. Padding is deliberately absent. Format.padLeft and padRight already take a width and a fill character, so a String spelling would be a second way to do one thing. That is worth recording because the estimate for this PR was nine members and the audit of what already existed is what removed one. Also states the cost on every String member, which the module was missing almost entirely. contains and tryIndexOf are O(n*m) worst case, being searches rather than lookups, which is the one a reader would assume wrong; the whole-string operations are O(n), slice is O(k) in the slice, and repeat is O(n*k).
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Two dogfooding reports from real programs, and the standard-library sweep they triggered. Language: * a `type` declaration can name an imported type, bare or module-qualified (#36) — the one gap that changed a program's architecture rather than its phrasing, forcing two modules into one file * field access resolves from the base's type when it is known, so two records may share a field name without prefixes (#37) * parameters destructure: tuples (#38), records (#40), and `_` * a direct self tail call lowers to a loop, so an interactive turn loop no longer walks the stack (#39, #41) Standard library — about 115 new members, taking every module to the F# core set: List (#42), Seq (#44), Set and Map (#46), String (#47), Option and Result (#48), then a member-by-member FSharp.Core audit (#51). Every built-in member now carries a one-line description and its complexity in hover and completion (#43, #49), enforced by tests. Fixes: * `pyfun run` on a single file gives the program its own stdin, so an interactive program is runnable by the command whose job is running programs (#35) * a partially applied lambda closes over its argument instead of being wrapped, so `List.map ((+) 2)` emits `lambda b: 2 + b` (#52) * every multi-argument callback's scheme put the effect variable on the wrong arrows, so `List.fold` could never accept an effectful folder (#51) * `Seq.empty` lowered to a bare `iter()`, a TypeError (#51) One source-incompatible change, which is why this is 0.4.0 and not 0.3.1: a dotted `extern` target whose module prefix cannot be decided from the text is now a compile error naming the `extern import` to add (#50). `sys.stdout.flush` used to emit `import sys.stdout` and fail at runtime; declaring `extern import sys` fixes it.
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Dogfooding finding #5, PR 4 of 5 (see #34). Branched from
main, so it is independent of #46 (Map/Set) — the two touch different regions and can merge in either order.Eight members, the smallest sweep because
Stringwas already the best-covered module:isEmptygetrepeattrimStarttrimEndsplitLinesrevofList.getis the one worth arguing about. It answersOptionand is bounds-checked, exactly likeList.get, and since there is nochartype a character comes back as a one-character string. Before this, reading one character meantString.slice i (i + 1)— total, but saying nothing about what it is for.isEmptytakes the name every other container already uses, soList/Set/Map/Seq/Stringnow all answer the same question the same way.Padding is deliberately absent.
Format.padLeft/padRightalready take a width and a fill character, so aStringspelling would be a second way to do one thing. Worth flagging because my estimate for this PR was nine members, and checking what already existed is what removed one — the same kind of check theFSharp.Coreaudit pass is for.The rest are the obvious gaps:
repeat,trimStart/trimEnd(stripalready did both ends),splitLines(splits on any line ending, and a trailing newline does not add an empty last line),rev, andofListas the inverse oftoList.Tests: 3 typecheck cases (monomorphic over
string,getansweringOption,ofListinvertingtoList), 1 lowering assertion (routes to Python's ownstrmethods), and an end-to-end program covering all eight including both clamping edges. Full suite, clippy and fmt clean.