Class: Idl::ForLoopAst

Inherits:
AstNode show all
Includes:
Executable, Returns
Defined in:
lib/idl/ast.rb

Instance Method Summary collapse

Constructor Details

#initialize(input, interval, init, condition, update, stmts) ⇒ ForLoopAst

Returns a new instance of ForLoopAst.



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# File 'lib/idl/ast.rb', line 5185

def initialize(input, interval, init, condition, update, stmts)
  super(input, interval, [init, condition, update] + stmts)
end

Instance Method Details

#condition ⇒ Object 



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# File 'lib/idl/ast.rb', line 5181

def condition = @children[1]

#execute_unknown(symtab) ⇒ void Originally defined in module Executable

This method returns an undefined value.

“execute” the statement, forcing any variable assignments to an unknown state This is used down unknown conditional paths.

Parameters:

  • symtab (SymbolTable) —

    The symbol table for the context

Raises:

  • ValueError if some part of the statement cannot be executed at compile time

#init ⇒ Object 



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# File 'lib/idl/ast.rb', line 5180

def init = @children[0]

#return_value(symtab) ⇒ Integer, ... Also known as: execute

Evaluate the compile-time return value of this node, or, if the node does not return (e.g., because it is an IfAst but there is no return on the taken path), execute the node and update the symtab

Parameters:

  • symtab (SymbolTable) —

    The symbol table for the context

Returns:

  • (Integer) —

    The return value, if it is integral

  • (Boolean) —

    The return value, if it is boolean

  • (nil) —

    if the return value is not compile-time-known

Raises:

  • ValueError if, during evaluation, a node without a compile-time value is found



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# File 'lib/idl/ast.rb', line 5203

def return_value(symtab)
  symtab.push(self)

  begin
    value_result = value_try do
      init.execute(symtab)

      while condition.value(symtab)
        stmts.each do |s|
          if s.is_a?(Returns)
            v = s.return_value(symtab)
            unless v.nil?
              return v
            end
          else
            s.execute(symtab)
          end
        end
        update.execute(symtab)
      end
    end
    value_else(value_result) do
      value_error ""
    end
  ensure
    symtab.pop
  end
  nil
end

#return_values(symtab) ⇒ Array<Integer>, Array<Boolean>

Evaluate all possible compile-time return values of this node, or, if the node does not return (e.g., because it is an IfAst but there is no return on a possible path), execute the node and update the symtab

Parameters:

  • symtab (SymbolTable) —

    The symbol table for the context

Returns:

  • (Array<Integer>) —

    The possible return values. Will be an empty array if there are no return values

  • (Array<Boolean>) —

    The possible return values. Will be an empty array if there are no return values

Raises:

  • ValueError if, during evaluation, a node without a compile-time value is found



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# File 'lib/idl/ast.rb', line 5234

def return_values(symtab)
  value_result = value_try do
    # if there is a known return value, then we are done
    return [return_value(symtab)]
  end
  value_else(value_result) do
    # see if we can collect a list
    values = []
    symtab.push(self)

    begin
      value_result = value_try do
        init.execute(symtab)

        while condition.value(symtab)
          stmts.each do |s|
            if s.is_a?(Returns)
              value_result = value_try do
                v = s.return_value(symtab)
                unless v.nil?
                  return values.push(v).uniq
                end
              end
              value_else(value_result) do
                values += s.return_values(symtab)
              end
            else
              s.execute(symtab)
            end
          end
          update.execute(symtab)
        end
        :ok
      end
    ensure
      symtab.pop
    end

    values.uniq
  end
end

#stmts ⇒ Object 



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# File 'lib/idl/ast.rb', line 5183

def stmts = @children[3..]

#to_idl ⇒ String

Return valid IDL representation of the node (and its subtree)

Returns:

  • (String) —

    IDL code for the node



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# File 'lib/idl/ast.rb', line 5280

def to_idl
  idl = "for (#{init.to_idl}; #{condition.to_idl}; #{update.to_idl}) {"
  stmts.each do |s|
    idl << s.to_idl
  end
  idl << "}"
  idl
end

#type_check(symtab) ⇒ void

This method returns an undefined value.

type check this node and all children

Calls to #type and/or #value may depend on type_check being called first with the same symtab. If not, those functions may raise an AstNode::InternalError

Parameters:

Raises:



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# File 'lib/idl/ast.rb', line 5190

def type_check(symtab)
  symtab.push(self)
  init.type_check(symtab)
  condition.type_check(symtab)
  update.type_check(symtab)

  stmts.each do |s|
    s.type_check(symtab)
  end
  symtab.pop
end

#update ⇒ Object 



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# File 'lib/idl/ast.rb', line 5182

def update = @children[2]