Languages

What you'll learn

• How to introspect any loaded language.

Complete example

examples/language.zig prints the bundled grammar's metadata, all 15 symbols with flags, and resolves a symbol and a field by name.

Running the example

zig build run-language

Expected output

language: expression abi=15 symbols=15 states=18
  #0 end named=false visible=false
  #1 identifier named=true visible=true
  #2 number named=true visible=true
  #3 + named=false visible=true
  #4 - named=false visible=true
  #5 * named=false visible=true
  #6 / named=false visible=true
  #7 ( named=false visible=true
  #8 ) named=false visible=true
  #9 whitespace named=false visible=false
  #10 program named=true visible=true
  #11 expression named=true visible=true
  #12 term named=true visible=true
  #13 factor named=true visible=true
  #14 ERROR named=true visible=true
symbol for "+": 3
field id for "left": 1 (left)

How it works

Symbols 0–9 are terminals (tokens), 10–13 the grammar's non-terminals, 14 the error symbol. Anonymous tokens (+, () are visible but not named — they appear in trees without counting as named children. left/right fields are bound on the binary productions.

A second bundled grammar, sexp_language, covers nested lists — try zig build run-sexp_parse:

root: program [0, 17]
grouped list aliased to: sequence text='add 1 (mul 2 3)'
sequence matches: 2

A third, json_language, covers real JSON — try zig build run-json_parse:

root: program has_error=false
first pair: key="name" value="ada"
strings: 4
  "name"
  "ada"
  "scores"
  "admin"

And outline_language demonstrates external scanners — try zig build run-external_scanner:

root: program has_error=false
header: # Shopping
header: # Fruit

API used

• Language, Symbols, Fields.

Related guides

• Language Definition