+++ /dev/null
-# This file is part of NIT ( http://www.nitlanguage.org ).
-#
-# Copyright 2015 Julien Pagès <julien.pages@lirmm.fr>
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# Handle all numbering operations related to local variables in the Nit virtual machine
-module variables_numbering
-
-import vm
-
-redef class VirtualMachine
-
- # The frames of the VirtualMachine are specialized
- redef type FRAME: VmFrame
-
- # Number the variables in `n`.
- # Do nothing if `n` is null
- fun numbering(n: nullable AExpr, position: Int): Int
- do
- if n == null then return position
-
- var pos = n.numbering(self, position)
- return pos
- end
-
- # Redef to add the numbering of variables and arguments
- redef fun new_frame(node, mpropdef, args)
- do
- var f = new VmFrame(node, mpropdef, args)
-
- # If this Frame is for a method then number variables into the body of the method
- if node isa AMethPropdef then
- # Number the variables
- if not node.is_numbering then node.numbering_variables(self, mpropdef.as(MMethodDef))
-
- # Create an empty environment
- f.variables = new Array[Instance].filled_with(initialization_value, node.environment_size)
- end
-
- # If this Frame is for an attribute with a block then number the block
- if node isa AAttrPropdef then
- # Number the variables
- if not node.is_numbering then node.numbering_variables(self)
-
- # Create an empty environment
- f.variables = new Array[Instance].filled_with(initialization_value, node.environment_size)
- end
-
- # Putting self at the beginning of the environment
- f.variables[0] = args[0]
- return f
- end
-
- # Read a `Variable` from a frame by using its position
- redef fun read_variable(v: Variable): Instance
- do
- return frame.variables[v.position]
- end
-
- # Assign the value of the `Variable` in an environment
- redef fun write_variable(v: Variable, value: Instance)
- do
- frame.variables[v.position] = value
- end
-end
-
-redef class Variable
- # The position in the environment
- var position: Int
-end
-
-# Implementation of a Frame with numbered variables
-class VmFrame
- super Frame
-
- # Contains the value of Variables (which are numbered)
- var variables: Array[Instance] = new Array[Instance]
-end
-
-redef class AExpr
- # Give a position to each variable declared in the node.
- # NOTE: Do not call this method directly, but use `v.numbering`
- # This method is here to be implemented by subclasses.
- # *`v` The current instance of the virtual machine
- # *`position` The first available position in the environment a variable can have
- # Return the next available position a variable can have
- public fun numbering(v: VirtualMachine, position: Int): Int
- do
- return position
- end
-end
-
-redef class APropdef
- # Indicate if the variables numbering has been done
- private var is_numbering: Bool = false
-
- # The size of the environment to create to call this method
- private var environment_size: Int = 0
-end
-
-redef class AMethPropdef
- # Assign a position in the environment to each local variable of `mpropdef`
- # *`v` The current VirtualMachine
- # *`mpropdef` The method to number
- private fun numbering_variables(v: VirtualMachine, mpropdef: MMethodDef)
- do
- # The position in the environment
- var position = 0
-
- # The `self` variable has the first position
- if self.selfvariable != null then
- self.selfvariable.position = position
- position += 1
- end
-
- # Number the parameters
- for i in [0..mpropdef.msignature.arity[ do
- var variable = self.n_signature.n_params[i].variable
- variable.as(not null).position = position
- position += 1
- end
-
- # Recursively go into the AST nodes to number all local variables
- if n_block != null then
- position = v.numbering(self.n_block, position)
- end
-
- is_numbering = true
-
- # The size of the environment to create to execute a call to this method
- environment_size = position
- end
-end
-
-redef class AAttrPropdef
- # Assign a position in the environment to each local variable of `mpropdef`
- # *`v` The current VirtualMachine
- private fun numbering_variables(v: VirtualMachine)
- do
- # The position in the environment
- var position = 0
-
- # The `self` variable has the first position
- if self.selfvariable != null then
- self.selfvariable.position = position
- position += 1
- end
-
- # Recursively go into the AST nodes to number all local variables
- if n_block != null then
- position = v.numbering(self.n_block, position)
- end
-
- is_numbering = true
-
- # The size of the environment to create to execute a call to this method
- environment_size = position
- end
-end
-
-redef class AVardeclExpr
- redef fun numbering(v, position)
- do
- # Attribute a position to this variable
- self.variable.as(not null).position = position
- position += 1
-
- # Recursively continue to numbering the variables
- position = v.numbering(self.n_expr, position)
-
- # `position` is the next available position in the environment
- return position
- end
-end
-
-redef class ABlockExpr
- redef fun numbering(v, position)
- do
- for e in self.n_expr do
- position = v.numbering(e, position)
- end
- return position
- end
-end
-
-redef class AIfExpr
- redef fun numbering(v, position)
- do
- # Attribute numbers separetely for the two branches
- var pos = v.numbering(self.n_then, position)
- var pos1 = v.numbering(self.n_else, position)
-
- if pos > pos1 then
- return pos
- else
- return pos1
- end
- end
-end
-
-redef class AIfexprExpr
- redef fun numbering(v, position)
- do
- # Attribute numbers separetely for the two branches
- var pos = v.numbering(self.n_then, position)
- var pos1 = v.numbering(self.n_else, position)
-
- if pos > pos1 then
- return pos
- else
- return pos1
- end
- end
-end
-
-redef class ADoExpr
- redef fun numbering(v, position)
- do
- return v.numbering(self.n_block, position)
- end
-end
-
-redef class AWhileExpr
- redef fun numbering(v, position)
- do
- return v.numbering(self.n_block, position)
- end
-end
-
-redef class ALoopExpr
- redef fun numbering(v, position)
- do
- return v.numbering(self.n_block, position)
- end
-end
-
-redef class AForExpr
- redef fun numbering(v, position)
- do
- # Give a position to each variable declared in the header of the for
- if self.variables.length == 1 then
- self.variables.first.position = position
- self.variables[0].position = position
- position += 1
- else if self.variables.length == 2 then
- self.variables[0].position = position
- position += 1
- self.variables[1].position = position
- position += 1
- end
- return v.numbering(self.n_block, position)
- end
-end
-
-redef class AArrayExpr
- redef fun numbering(v, position)
- do
- for nexpr in self.n_exprs do
- position = v.numbering(nexpr, position)
- end
- return position
- end
-end
nitlanguage / nit.git / blobdiff