Class: Idl::FieldAccessExpressionAst

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

Overview

represents a bitfield or struct field access (rvalue)

for example:

entry.PPN

Instance Method Summary collapse

Constructor Details

#initialize(input, interval, bitfield, field_name) ⇒ FieldAccessExpressionAst

Returns a new instance of FieldAccessExpressionAst.

[View source]

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# File 'lib/idl/ast.rb', line 3367

def initialize(input, interval, bitfield, field_name)
  super(input, interval, [bitfield])

  @field_name = field_name
end

Instance Method Details

#kind(symtab) ⇒ Object

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# File 'lib/idl/ast.rb', line 3373

def kind(symtab)
  obj.type(symtab).kind
end

#obj ⇒ Object

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# File 'lib/idl/ast.rb', line 3365

def obj = @children[0]

#to_idl ⇒ String

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

Returns:

  • (String) —

    IDL code for the node

[View source]

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# File 'lib/idl/ast.rb', line 3420

def to_idl = "#{obj.to_idl}.#{@field_name}"

#type(symtab) ⇒ Type

Given a specific symbol table, return the type of this node.

Should not be called until #type_check is called with the same arguments

Parameters:

Returns:

  • (Type) —

    The type of the node

Raises:

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# File 'lib/idl/ast.rb', line 3378

def type(symtab)
  obj_type = obj.type(symtab)

  if obj_type.kind == :bitfield
    Type.new(:bits, width: obj_type.range(@field_name).size)
  elsif obj_type.kind == :struct
    obj_type.member_type(@field_name)
  else
    internal_error "huh? #{obj.text_value} #{obj_type.kind}"
  end
end

#type_check(symtab) ⇒ Object

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# File 'lib/idl/ast.rb', line 3390

def type_check(symtab)
  obj.type_check(symtab)

  obj_type = obj.type(symtab)

  if obj_type.kind == :bitfield
    internal_error "#{bitfield.text_value} Not a BitfieldType (is a #{obj_type.class.name})" unless obj_type.respond_to?(:field_names)
    unless obj_type.field_names.include?(@field_name)
      type_error "#{@field_name} is not a member of #{obj_type}"
    end
  elsif obj_type.kind == :struct
    type_error "#{@field_name} is not a member of #{obj_type}" unless obj_type.member?(@field_name)
  else
    type_error "#{obj.text_value} is not a bitfield (is #{obj.type(symtab)})"
  end
end

#value(symtab) ⇒ Object

Return the compile-time-known value of the node

[View source]

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# File 'lib/idl/ast.rb', line 3408

def value(symtab)
  if kind(symtab) == :bitfield
    range = obj.type(symtab).range(@field_name)
    (obj.value(symtab) >> range.first) & ((1 << range.size) - 1)
  elsif kind(symtab) == :struct
    obj.value(symtab)[@field_name]
  else
    type_error "#{obj.text_value} is Not a bitfield."
  end
end

#values(symtab) ⇒ Array<Integer>, ... Originally defined in module Rvalue

Return a complete list of possible compile-time-known values of the node, or raise a ValueError if the full list cannot be determined

For most AstNodes, this will just be a single-entry array

Parameters:

  • symtab (SymbolTable) —

    The context for the evaluation

Returns:

  • (Array<Integer>) —

    The complete list of compile-time-known values, when they are integral

  • (Array<Boolean>) —

    The complete list of compile-time-known values, when they are booleans

  • (AstNode::ValueError) —

    if the list of values is not knowable at compile time