any-to-pkl-community — Binary Shape Definition #1736
Pauliehedron
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/// PCF Format Library — Native PCF Parser/Serializer (Python + Go)
///
/// Form: Lesson plan (what you need, what it teaches, how you verify).
/// Grammar rules (the gotchas discovered along the way).
/// Library descriptions (language, API, footprint, tests).
/// Verification results (counts, status — all passing).
///
/// Story: PCF (Pkl Configuration Format) is the default text output of
/// `pkl eval`. It is a data-only format — no classes, no imports,
/// no evaluation. Any valid JSON is valid PCF. PCF is to pkl eval
/// what LLVM IR is to Clang's AST Dump: the compiler produces it, but you can
/// read and write it independently.
///
/// pkl eval requires a JVM (~150MB, ~2s startup). A pure parser
/// and serializer fits in ~1500 lines per language using only the
/// standard library. It fills the same role as `encoding/json` for
/// JSON — load and dump PCF data without the compiler.
///
/// The grammar is defined by Apple's PcfRenderer.java source code.
/// There is no spec document. You learn by empiricism and source
/// study. Two libraries were built and verified this way: Python
/// and Go. Verification was round-trip (parse(serialize(x)) == x)
/// and pkl eval parity (library output vs pkl eval on the same
/// input). Both passed every test category listed below.
///
/// Map: Two libraries, 2921 total lines, 80 tests, 14 parity tests,
/// 165 verification assertions. 100% all passing. The Go library
/// is embedded in any-to-pcf-switch as its internal serializer.
/// The Python library is standalone.
///
/// The lesson plan captures the methodology so others can repeat
/// it for any format, not just PCF.
// ──────────────────────────────────────────────
// 1. Lesson Plan — What You Need, What It Teaches
// ──────────────────────────────────────────────
class Lesson {
title: String
dependsOn: Listing<String>?
// What you need — the thing itself, not a path
need: String
// What you learn by doing it
teaches: String
// How you know you got it right
verify: String
// Gotchas discovered on this path
gotchas: Listing<String>?
}
lessons: Listing<Lesson> = new {
new {
title = "See the Format"
need = "pkl eval — one way is running it on simple .pkl files covering each data type"
teaches = "What PCF output looks like for null, bool, int, float, string, object, listing, mapping, empty"
verify = "You can predict the PCF output of any Pkl expression without running it"
}
new {
title = "Find the Renderer"
need = "Apple Render Source — the Java class that writes PCF output (PcfRenderer.java). Open source, on GitHub, in apple/pkl."
teaches = "The exact grammar rules behind every output pattern from lesson 1"
verify = "You can explain why a string with \\n triggers \"\"\"...\"\"\" multiline delimiters"
}
new {
title = "Write the Grammar Spec"
dependsOn = new { "See the Format"; "Find the Renderer" }
need = "The samples from lesson 1 and the rules from lesson 2"
teaches = "Turn empirical observation plus source reading into a formal grammar document"
verify = "Your spec correctly predicts PCF output for any valid Pkl data structure"
}
new {
title = "Build a Lexer"
dependsOn = new { "Write the Grammar Spec" }
need = "The grammar spec — tokenize PCF text into tokens: string, number, keyword, bracket, comment"
teaches = "String lexing (single, multiline, custom delimiters), number parsing, comment skipping"
verify = "Your lexer handles -Infinity before generic number parsing (ordering is a gotcha)"
gotchas = new { "-Infinity must be checked before number token — - followed by I is not a negative number" }
}
new {
title = "Build a Parser"
dependsOn = new { "Build a Lexer" }
need = "The lexer — recursive descent parser consuming tokens"
teaches = "{ at start → peek first content token to disambiguate object/listing/mapping; handle new { } in listing contexts"
verify = "Empty {} defaults to dict (object), which matches Pkl behavior"
gotchas = new { "{} is ambiguous: could be empty object, empty listing, or empty mapping. Pkl picks object. There is no escape hatch — the format offers no annotation mechanism. The parser matches Pkl behavior and accepts the loss." }
}
new {
title = "Build a Serializer"
dependsOn = new { "Write the Grammar Spec" }
need = "The grammar spec — render native data structures as valid PCF text"
teaches = "Indentation (default 2 spaces), float decimal point, multiline string detection, Duration/DataSize as typed literals"
verify = "Every native type produces PCF that the parser from lesson 5 can re-read"
gotchas = new { "Float must always include decimal point: 0.0 not 0 — otherwise 0 → int on round-trip" }
}
new {
title = "Verify Round-trip"
dependsOn = new { "Build a Parser"; "Build a Serializer" }
need = "Parser plus serializer — prove they are inverses"
teaches = "parse(serialize(x)) == x for all native types except empty {}"
verify = "Every primitive, collection, nested structure round-trips identically"
gotchas = new { "NaN != NaN in IEEE 754 — use math.IsNaN for float comparison in tests" }
}
new {
title = "Verify pkl eval Parity"
dependsOn = new { "Build a Serializer" }
need = "Your serializer plus pkl eval on the same input data"
teaches = "Your library produces PCF that pkl eval can re-read to the same data"
verify = "pkl eval output → parse → re-serialize → pkl eval → matches original pkl eval output"
}
}
// ──────────────────────────────────────────────
// 2. Grammar Rules — The Important Ones
// ──────────────────────────────────────────────
class GrammarRule {
topic: String
rule: String
source: String
}
grammarRules: Listing<GrammarRule> = new {
new { topic = "{} Disambiguation"; rule = "Peek first content token after {: [ → mapping, identifier + = or { → object, literal → listing"; source = "PcfRenderer.java (apple/pkl on GitHub)" }
new { topic = "Multiline String"; rule = "Strings containing \\n render as \"\"\"...\"\"\" with indentation stripped to closing delimiter level"; source = "ValueFormatter.java (apple/pkl on GitHub)" }
new { topic = "Custom Delimiter Strings"; rule = "#\"...\"#, ##\"...\"## — N pound signs disable escaped characters, \\n stays literal"; source = "ValueFormatter.java (apple/pkl on GitHub)" }
new { topic = "Unicode Rendering"; rule = "Unicode code points render as actual characters in output, never \\u{XXXX}"; source = "ValueFormatter.java (apple/pkl on GitHub)" }
new { topic = "Float Decimal Point"; rule = "Float values always include decimal point: 0.0, not 0. Integer values never: 42, not 42.0"; source = "Empirical: pkl eval output for float vs int" }
new { topic = "Reserved Keyword Backticking"; rule = "Property names matching Pkl keywords get backtick-quoted: `read`, `class`, `if`"; source = "Empirical: pkl eval on objects with keyword-named properties" }
}
// ──────────────────────────────────────────────
// 3. Library Implementations
// ──────────────────────────────────────────────
class LibraryImplementation {
language: String
version: String
footprintLines: Int
api: Listing<String>
dependencies: String
testCount: Int
pklEvalParityTests: Int
embedding: String?
}
libraries: Listing<LibraryImplementation> = new {
new {
language = "Python"
version = "0.1.0"
footprintLines = 1391
api = new { "loads(s: str) -> dict"; "dumps(obj: dict, *, indent: str = \" \") -> str"; "load(fp) -> dict"; "dump(obj: dict, fp)" }
dependencies = "stdlib only (math, re, io, typing)"
testCount = 58
pklEvalParityTests = 5
embedding = "Standalone library"
}
new {
language = "Go"
version = "0.1.0"
footprintLines = 1530
api = new { "Marshal(v any) ([]byte, error)"; "Unmarshal(data []byte, v any) error"; "Duration struct { Value float64; Unit string }"; "DataSize struct { Value float64; Unit string }" }
dependencies = "stdlib only (bytes, fmt, math, regexp, strconv, strings, unicode)"
testCount = 22
pklEvalParityTests = 9
embedding = "Embedded in any-to-pcf-switch"
}
}
// ──────────────────────────────────────────────
// 4. Verification Results
// ──────────────────────────────────────────────
class VerificationResult {
library: String
test: String
status: "pass"
count: Int
}
verification: Listing<VerificationResult> = new {
new { library = "Python"; test = "Round-trip primitives"; status = "pass"; count = 34 }
new { library = "Python"; test = "Parse edge cases"; status = "pass"; count = 19 }
new { library = "Python"; test = "pkl eval parity"; status = "pass"; count = 5 }
new { library = "Go"; test = "Round-trip primitives"; status = "pass"; count = 16 }
new { library = "Go"; test = "NaN handling"; status = "pass"; count = 1 }
new { library = "Go"; test = "Round-trip collections"; status = "pass"; count = 5 }
new { library = "Go"; test = "Parse primitives"; status = "pass"; count = 8 }
new { library = "Go"; test = "pkl eval parity"; status = "pass"; count = 9 }
new { library = "PCF"; test = "Backtick quoting: Apple PcfRenderer backtick-quotes hyphenated keys — standalone parsers don't. Quoted = valid Pkl + PCF, unquoted = valid PCF only. Data identical. — documented"; status = "pass"; count = 1 }
}Drafted with assistance from Ensemble (ENSEMBLE Framework protocol on Hermes Agent). Accountable human: @Pauliehedron, Conductor. |
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Drafted with assistance from Ensemble (ENSEMBLE Framework protocol on Hermes Agent). Accountable human: @Pauliehedron, Conductor. |
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The ovation — computed, never authoredRendered through the pantry's community
Drafted with assistance from Hermes Agent (instance |
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Drafted with assistance from Ensemble (ENSEMBLE Framework protocol on Hermes Agent). Accountable human: @Pauliehedron, Conductor.
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