fdb0f4ab83
- src/jolt/clojure/string.clj (123 lines, 20 functions): blank?, capitalize, lower-case, upper-case, includes?, join, replace, replace-first, str-reverse, split, starts-with?, ends-with?, trim, triml, trimr, trim-newline, escape, index-of, last-index-of - src/jolt/clojure/set.clj (124 lines, 10 operations): union, intersection, difference, select, project, rename, rename-keys, map-invert, join, index, subset?, superset? - src/jolt/clojure/walk.clj (77 lines, 9 functions): walk, postwalk, prewalk, postwalk-demo, prewalk-demo, postwalk-replace, prewalk-replace, keywordize-keys, stringify-keys, macroexpand-all - src/jolt/core.janet: 11 Janet string interop bindings (str-trim, str-upper, str-lower, str-find, str-replace, str-replace-all, str-reverse-b, str-join, str-split, str-triml, str-trimr) - test/phase10-test.janet: 2 test sections (40-41) 15+ assertions covering string and set functions - All .clj files use eval-form for multi-form loading - 315 ok, 2 fail (pre-existing, unchanged)
68 lines
No EOL
2.4 KiB
Markdown
68 lines
No EOL
2.4 KiB
Markdown
---
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name: jolt-gotchas
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description: Common pitfalls and workarounds discovered during Jolt implementation
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---
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# jolt-gotchas
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Recurring pitfalls and their fixes discovered across all implementation phases.
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## PHM/Set Metadata Key Leakage
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PHM and set internal keys (`:jolt/deftype`, `:cnt`, `:buckets`, `:_meta`, `:jolt/type`, `:phm`) leak into `pairs`/`keys` iteration. Must filter in merge, merge-with, keys, vals, and print-collection.
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```janet
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(when (and (not= k :jolt/deftype) (not= k :cnt)
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(not= k :buckets) (not= k :_meta)
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(not= k :jolt/type) (not= k :phm)) ...)
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```
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## Keywords with `#` Are Invalid Janet Literals
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`:#inst`, `:#uuid` cause parse errors. Use dynamic table construction:
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```janet
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(let [dr @{}] (put dr (keyword "#inst") fn) dr)
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```
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## Janet `break` Only Works in Loops
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Does NOT work inside `let`. Use `(var found nil)` + `(set found val) (break)` pattern.
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## Bare Tuples in `eval` Are Function Calls
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`(eval [1 2 3])` calls `1` as function. Use `['tuple 1 2 3]` in data-structure emitter.
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## Janet `case` for Multi-Arity
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Janet lacks Clojure-style multi-arity defn. Use `(defn f [& args] (case (length args) 1 ... 2 ...))`.
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## core-renames + core-fn-values Must Stay in Sync
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Both tables must be updated together when adding core fns. Missing entries = silent nil returns. `"-"` is `core-sub` NOT `core--`.
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## `set!` Field Mutation Reader Quirk
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`(set! (.-x obj) val)` parses as array with `.-x` symbol head — not as standalone `.-x` symbol. Check for this case before the `(. obj -field)` shorthand.
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## Janet `cond` Requires `true` Guard for Catch-All
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A bare expression in the last position of `cond` is treated as a **test** clause (not body). Use `true` as the test:
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```janet
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(cond (nil? x) (buf "nil") (number? x) (buf (string x)) true (buf (string x)))
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```
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Without `true`, the last expression executes as a side-effect test between branches. Hit us in buffer-based write-value — raw tuple addresses leaked into REPL output.
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## Janet `cond` Requires `true` Guard for Catch-All
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A bare expression in the last position of `cond` is treated as a **test** clause (not body). It executes between other branches as a side-effect test. Use `true` as the test to make it a proper catch-all:
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```janet
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(cond
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(nil? x) (buf "nil")
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(number? x) (buf (string x))
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true (buf (string x))) ; ← `true` required
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```
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Without `true`, `(push-str buf (string v))` in the last position leaked raw tuple addresses into REPL output. |