Module: TreeHaver::Backends::Parslet

Defined in:
lib/tree_haver/backends/parslet.rb

Overview

Note:

This backend requires a Parslet grammar class for the specific language

Parslet backend using pure Ruby PEG parser

This backend wraps Parslet-based parsers (like the toml gem) to provide a
pure Ruby alternative to tree-sitter. Parslet is a PEG (Parsing Expression
Grammar) parser generator written in Ruby that produces Hash/Array/Slice
results rather than a traditional AST.

Unlike tree-sitter backends which are language-agnostic runtime parsers,
Parslet parsers are grammar-specific and defined as Ruby classes. Each
language needs its own Parslet grammar (e.g., TOML::Parslet for TOML).

Examples:

Using with toml gem

require "toml"

parser = TreeHaver::Parser.new
# For Parslet, "language" is actually a grammar class
parser.language = TOML::Parslet
tree = parser.parse(toml_source)

See Also:

Defined Under Namespace

Classes: Language, Node, Parser, Tree

Class Method Summary collapse

Class Method Details

.available? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tree_haver/backends/parslet.rb', line 41

def available?
  return @loaded if @load_attempted # rubocop:disable ThreadSafety/ClassInstanceVariable
  @load_attempted = true # rubocop:disable ThreadSafety/ClassInstanceVariable
  begin
    require "parslet"
    @loaded = true # rubocop:disable ThreadSafety/ClassInstanceVariable
  rescue LoadError
    @loaded = false # rubocop:disable ThreadSafety/ClassInstanceVariable
  rescue StandardError
    @loaded = false # rubocop:disable ThreadSafety/ClassInstanceVariable
  end
  @loaded # rubocop:disable ThreadSafety/ClassInstanceVariable
end

.capabilities ⇒ Hash{Symbol => Object}

Get capabilities supported by this backend

Examples:

TreeHaver::Backends::Parslet.capabilities
# => { backend: :parslet, query: false, bytes_field: true, incremental: false }

Returns:

  • (Hash{Symbol => Object}) —

    capability map



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# File 'lib/tree_haver/backends/parslet.rb', line 70

def capabilities
  return {} unless available?
  {
    backend: :parslet,
    query: false,          # Parslet doesn't have a query API like tree-sitter
    bytes_field: true,     # Parslet::Slice provides offset and length
    incremental: false,    # Parslet doesn't support incremental parsing
    pure_ruby: true,       # Parslet is pure Ruby (portable)
  }
end

.reset! ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method returns an undefined value.

Reset the load state (primarily for testing)



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# File 'lib/tree_haver/backends/parslet.rb', line 59

def reset!
  @load_attempted = false # rubocop:disable ThreadSafety/ClassInstanceVariable
  @loaded = false # rubocop:disable ThreadSafety/ClassInstanceVariable
end