Grammar — Pudu

type: grammar language: Pudu version: "0.1.2" tags: [grammar] aliases: [Grammar — Pudu, Pudu Grammar]

The Pudu surface this repository is written against, pinned to compiler 0.1.2 as published in its release archive. Where this page and the compiler disagree, the compiler wins and this page is corrected in the same change.

SDK Discovery Map

Imports / Namespaces

• One module per file; the module name is the path under its source root with / as .: src/PuduLangDocgen/Paths.pudu is module PuduLangDocgen.Paths.
• Every import is qualified and aliased: import Std.Sync as Sync. Nothing is imported implicitly.
• A trait's methods are callable on a value wherever its module is imported; the trait itself is not imported.
• Suites under test/ and programs under examples/ import package modules through the manifest's source root.

Core Primitives

• Records: export type Property = { name: Str, value: Value }, built as Property{name: "Id", value: v}, updated as Property{..p, name: "Other"}.
• Sum types may be recursive through arrays and records: Value holds Array[Value] and Structure, whose Property holds a Value again.
• A variant may share its name with a type: Scalar(Scalar) is the Value variant holding a Scalar.
• A function stored in a record field is called as (record.field)(argument).
• A trait may be implemented for built-in types (impl Capturable for Int), and a generic function may require it: fn of[T: Capturable](held: T) -> Value.
• show(value) and == work on values of any type.
• Option[T] and Result[T, E] helpers are module functions (Option.unwrapOr(value, fallback)).
• Module scope holds only const. Lookup tables are const arrays or maps built with mapOf([...]). A const cannot call a function, so shared state is created by a function and passed on.
• Closures: fn(x: Int) -> Int { x + 1 }, or the short form |x: Int| x + 1. A closure captures a copy of every binding it names; state that later calls must observe lives in a Sync.Cell.
• Borrowing: &T parameters are read-only views; *view copies a borrowed value into an owned one.

Numbers

• Int arithmetic is checked: an addition or multiplication past the 64-bit range stops the program. Hashes reduce every intermediate result with % so it stays in range.
• There is no built-in conversion between Int and Float64. A float is read as a Decimal through its text: show(f).toDecimal().
• show renders a float in the shortest form that reads back, switching to an exponent for large and small magnitudes (1.0e30, 1.0e-7); display formatting goes through Decimal instead.
• Infinity and NaN have no Decimal; their text is Infinity and NaN.

Text

• String indices and lengths count characters, not bytes: "héllo".length() is 5.
• slice, take, drop, indexOf, split, replace, chars, toUpper, toLower, trim, startsWith, endsWith, contains are methods on Str.
• Text is assembled as an array of pieces joined once at the end, not by repeated + in a loop.

Architectural laws

Pure modules produce values; Docset and Command alone perform effects. Every shipped module is rooted at PuduLangDocgen. All output paths and browser destinations are checked before use. Namespace anchors on files/types; concise /// contracts on every function and constant. Pudu formatter owns whitespace. No ambient global mutation or ignored effect failures.

Referenced by

[[00-INDEX]] · [[src/_MOC]]