Class: Autoproj::RosConditionParser

Inherits:
Parslet::Parser
  • Object
show all
Defined in:
lib/autoproj/ros_condition_parser.rb

Overview

Parses a conditional expression Syntax and rules as defined in www.ros.org/reps/rep-0149.html#id20

Defined Under Namespace

Classes: Transform

Constant Summary collapse

RESERVED = 
%w[and or].freeze

Instance Method Summary collapse

Constructor Details

#initialize(&expander) ⇒ RosConditionParser

Returns a new instance of RosConditionParser.



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# File 'lib/autoproj/ros_condition_parser.rb', line 11

def initialize(&expander)
    @expander = expander
    super()
end

Instance Method Details

#any_of(strings) ⇒ Object 



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# File 'lib/autoproj/ros_condition_parser.rb', line 35

def any_of(strings)
    strings = strings.dup
    strings.reduce(str(strings.shift)) { |acc, s| acc | str(s) }
end

#chain(lhs, operator, operation) ⇒ Object 



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# File 'lib/autoproj/ros_condition_parser.rb', line 46

def chain(lhs, operator, operation)
    (lhs.as(:lhs) >> operator >> operation.as(:rhs)) | lhs
end

#evaluate(expr) ⇒ Object 



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# File 'lib/autoproj/ros_condition_parser.rb', line 29

def evaluate(expr)
    Transform.new.apply(parse(expr.strip), expander: method(:expand))
rescue Parslet::ParseFailed => e
    raise Autoproj::ConfigError, e.message
end

#expand(var) ⇒ Object 



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# File 'lib/autoproj/ros_condition_parser.rb', line 16

def expand(var)
    @expander.call(var)
end

#quoted_literal(quote) ⇒ Object 



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# File 'lib/autoproj/ros_condition_parser.rb', line 40

def quoted_literal(quote)
    str(quote) >> (
        str(quote).absent? >> any
    ).repeat.maybe.as(:literal) >> str(quote)
end