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# frozen_string_literal: true
require_relative './front_end/parser'
require_relative './ast/ast_visitor'
require_relative './back_end/engine'
module Loxxy
# A Lox tree-walking interpreter.
# It acts as a facade object that:
# - hides the internal plumbings of the front-end and back-end parts.
# - delegates all the core work to its subordinate objects.
# @note WIP: very crude implementation.
class Interpreter
# return [Hash]
attr_reader :config
# @param theOptions [Hash]
def initialize(theOptions = {})
@config = theOptions
end
# Evaluate the given Lox program.
# Return the result of the last executed expression (if any)
# @param lox_input [String] Lox program to evaluate
# @return [Loxxy::Datatype::BuiltinDatatype]
def evaluate(lox_input)
raw_evaluate(lox_input).first
end
# Evaluate the given Lox program.
# Return the pair [result, a BackEnd::Engine instance]
# where result is the value of the last executed expression (if any)
# @param lox_input [String] Lox program to evaluate
# @return Loxxy::Datatype::BuiltinDatatype, Loxxy::BackEnd::Engine]
def raw_evaluate(lox_input)
# Front-end scans, parses the input and blurps an AST...
parser = FrontEnd::Parser.new
# The AST is the data object passed to the back-end
ast_tree = parser.parse(lox_input)
visitor = Ast::ASTVisitor.new(ast_tree)
# Back-end launches the tree walking & responds to visit events
# by executing the code determined by the visited AST node.
engine = BackEnd::Engine.new(config)
result = engine.execute(visitor)
[result, engine]
end
end # class
end # module
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22 entries across 22 versions & 1 rubygems