Syntax.Source

Source identity for the versioned syntax artifacts: source files and half-open byte spans.

Byte offsets are the canonical position vocabulary (line and column are projections for people, never a second identity), and these are the Prism-side types the token and surface-syntax exports decode into.

Types

Span

type Span = Span { lo: Int, hi: Int } deriving (Eq, Show)

A half-open byte range [lo, hi) into one source text.

span_len(Span { lo = 3, hi = 8 })

5

SourceFile

type SourceFile = SourceFile { digest: String, text: String } deriving (Eq)

One source file as an artifact embeds it: the exact text and its digest. Every span in an artifact indexes this text, so a persisted document needs no external file.

Functions and Values

span_len

span_len : (Syntax.Source.Span) -> Int

The number of bytes a span covers.

span_valid

span_valid : (Syntax.Source.Span) -> Bool

Whether a span is well formed: non-negative start, start at or before end.

(span_valid(Span { lo = 2, hi = 2 }), span_valid(Span { lo = 5, hi = 4 }))

(true, false)

span_contains

span_contains : (Syntax.Source.Span, Int) -> Bool

Whether a byte offset falls inside the span (half-open, so the end offset is outside).

line_col

line_col : (String, Int) -> (Int, Int)

The one-based line and column of a byte offset, as a projection over the text. Offsets past the end clamp to the final position.

line_col("ab\ncd", 4)

(2, 2)