Class: HeadMusic::Notation::LilyPond::Parser

Inherits:

Object

• Object
• HeadMusic::Notation::LilyPond::Parser

Defined in:

lib/head_music/notation/lily_pond/parser.rb

Overview

Interprets a LilyPond string as a HeadMusic::Content::Flow.

The pipeline validates in stages — blank input, lexing, delimiter balance, then the document's structure and every pitch, duration, key, and meter — before a flow is built, so a caller never receives a reference to a partially built flow. Unsupported constructs are named by the reader rather than swept up front, so one inside a \layout or \midi block the reader skips never reaches a caller.

Instance Method Summary

• #build_flow ⇒ Object private
• #flow ⇒ Object
• #initialize(lily_pond_string) ⇒ Parser constructor

  A new instance of Parser.

Constructor Details

#initialize(lily_pond_string) ⇒ Parser

Returns a new instance of Parser.

# File 'lib/head_music/notation/lily_pond/parser.rb', line 12

def initialize(lily_pond_string)
  @lily_pond_string = lily_pond_string
end

Instance Method Details

#build_flow ⇒ Object (private)

# File 'lib/head_music/notation/lily_pond/parser.rb', line 22

def build_flow
  ParsePreflight.ensure_input_present(@lily_pond_string)
  tokens = Lexer.new(@lily_pond_string).tokens
  ParsePreflight.ensure_balanced_delimiters(tokens)
  document = DocumentReader.new(tokens).document
  FlowBuilder.new(document).flow
end

#flow ⇒ Object

# File 'lib/head_music/notation/lily_pond/parser.rb', line 16

def flow
  @flow ||= build_flow
end