Class: Idl::MultiVariableAssignmentAst

Inherits:
AstNode
  • Object
show all
Includes:
Executable
Defined in:
lib/idl/ast.rb

Overview

represents assignement of multiple variable from a function call that returns multiple values

for example:

(match_result, cfg) = pmp_match<access_size>(paddr);

Instance Method Summary collapse

Constructor Details

#initialize(input, interval, variables, function_call) ⇒ MultiVariableAssignmentAst

Returns a new instance of MultiVariableAssignmentAst.



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# File 'lib/idl/ast.rb', line 2079

def initialize(input, interval, variables, function_call)
  super(input, interval, variables + [function_call])
end

Instance Method Details

#execute(symtab) ⇒ void

This method returns an undefined value.

“execute” the statement by updating the variables in the symbol table

Parameters:

  • symtab (SymbolTable) —

    The symbol table for the context

Raises:

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



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# File 'lib/idl/ast.rb', line 2124

def execute(symtab)
  value_result = value_try do
    values = function_call.execute(symtab)

    i = 0
    variables.each do |v|
      next if v.type(symtab).global?

      var = symtab.get(v.text_value)
      internal_error "call type check" if var.nil?

      var.value = values[i]
      i += 1
    end
  end
  value_else(value_result) do
    variables.each do |v|
      symtab.get(v.text_value).value = nil
    end
    value_error "value of right-hand side of multi-variable assignment is unknown"
  end
end

#execute_unknown(symtab) ⇒ void

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



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# File 'lib/idl/ast.rb', line 2148

def execute_unknown(symtab)
  variables.each do |v|
    symtab.get(v.text_value).value = nil
  end
end

#function_call ⇒ Object 



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# File 'lib/idl/ast.rb', line 2077

def function_call = @children.last

#rhs ⇒ Object 



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# File 'lib/idl/ast.rb', line 2088

def rhs
  function_call
end

#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 2155

def to_idl = "(#{variables.map(&:to_idl).join(', ')}) = #{function_call.to_idl}"

#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 2093

def type_check(symtab)
  function_call.type_check(symtab)
  variables.each { |var| var.type_check(symtab) }

  type_error "Assigning value to a constant" if variables.any? { |v| v.type(symtab).const? }

  type_error "Function '#{function_call.name}' has no return type" if function_call.type(symtab).nil?
  unless function_call.type(symtab).kind == :tuple
    type_error "Function '#{function_call.name}' only returns 1 variable"
  end

  if function_call.type(symtab).tuple_types.size != vars.size
    type_error "function '#{function_call.name}' returns #{function_call.type(symtab).tuple_types.size} arguments, but  #{variables.size} were specified"
  end

  function_call.type(symtab).tuple_types.each_index do |i|
    next if variables[i].is_a?(DontCareLvalueAst)
    raise "Implementation error" if variables[i].is_a?(DontCareReturnAst)

    var = symtab.get(variables[i].text_value)
    type_error "No symbol named '#{variables[i].text_value}'" if var.nil?

    internal_error "Cannot determine type of #{variables[i].text_value}" unless var.respond_to?(:type)

    unless var.type.convertable_to?(function_call.type(symtab).tuple_types[i])
      type_error "'#{function_call.name}' expecting a #{function_call.type(symtab).tuple_types[i]} in argument #{i}, but was given #{var.type(symtab)}"
    end
  end
end

#variables ⇒ Object 



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# File 'lib/idl/ast.rb', line 2076

def variables = @children[0..-2]

#vars ⇒ Array<AstNode>

Returns The variables being assigned, in order.

Returns:

  • (Array<AstNode>) —

    The variables being assigned, in order



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# File 'lib/idl/ast.rb', line 2084

def vars
  variables
end