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require 'mustermann/ast/translator'
module Mustermann
module AST
# Checks the AST for certain validations, like correct capture names.
#
# Internally a poor man's visitor (abusing translator to not have to implement a visitor).
# @!visibility private
class Validation < Translator
# Runs validations.
#
# @param [Mustermann::AST::Node] ast to be validated
# @return [Mustermann::AST::Node] the validated ast
# @raise [Mustermann::AST::CompileError] if validation fails
# @!visibility private
def self.validate(ast)
new.translate(ast)
ast
end
translate(Object, :splat) {}
translate(:node) { t(payload) }
translate(Array) { each { |p| t(p)} }
translate(:capture) { t.check_name(name, forbidden: ['captures', 'splat'])}
translate(:variable, :named_splat) { t.check_name(name, forbidden: 'captures')}
# @raise [Mustermann::CompileError] if name is not acceptable
# @!visibility private
def check_name(name, options = {})
forbidden = options[:forbidden]
raise CompileError, "capture name can't be empty" if name.nil? or name.empty?
raise CompileError, "capture name must start with underscore or lower case letter" unless name =~ /^[a-z_]/
raise CompileError, "capture name can't be #{name}" if Array(forbidden).include? name
raise CompileError, "can't use the same capture name twice" if names.include? name
names << name
end
# @return [Array<String>] list of capture names in tree
# @!visibility private
def names
@names ||= []
end
end
end
end
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