mirror of
https://github.com/amix/vimrc
synced 2024-12-29 21:33:06 +00:00
117 lines
3.8 KiB
Text
117 lines
3.8 KiB
Text
The **Scope** class regulates lexical scoping within CoffeeScript. As you
|
|
generate code, you create a tree of scopes in the same shape as the nested
|
|
function bodies. Each scope knows about the variables declared within it,
|
|
and has a reference to its parent enclosing scope. In this way, we know which
|
|
variables are new and need to be declared with `var`, and which are shared
|
|
with external scopes.
|
|
|
|
Import the helpers we plan to use.
|
|
|
|
{extend, last} = require './helpers'
|
|
|
|
exports.Scope = class Scope
|
|
|
|
The `root` is the top-level **Scope** object for a given file.
|
|
|
|
@root: null
|
|
|
|
Initialize a scope with its parent, for lookups up the chain,
|
|
as well as a reference to the **Block** node it belongs to, which is
|
|
where it should declare its variables, and a reference to the function that
|
|
it belongs to.
|
|
|
|
constructor: (@parent, @expressions, @method) ->
|
|
@variables = [{name: 'arguments', type: 'arguments'}]
|
|
@positions = {}
|
|
Scope.root = this unless @parent
|
|
|
|
Adds a new variable or overrides an existing one.
|
|
|
|
add: (name, type, immediate) ->
|
|
return @parent.add name, type, immediate if @shared and not immediate
|
|
if Object::hasOwnProperty.call @positions, name
|
|
@variables[@positions[name]].type = type
|
|
else
|
|
@positions[name] = @variables.push({name, type}) - 1
|
|
|
|
When `super` is called, we need to find the name of the current method we're
|
|
in, so that we know how to invoke the same method of the parent class. This
|
|
can get complicated if super is being called from an inner function.
|
|
`namedMethod` will walk up the scope tree until it either finds the first
|
|
function object that has a name filled in, or bottoms out.
|
|
|
|
namedMethod: ->
|
|
return @method if @method.name or !@parent
|
|
@parent.namedMethod()
|
|
|
|
Look up a variable name in lexical scope, and declare it if it does not
|
|
already exist.
|
|
|
|
find: (name) ->
|
|
return yes if @check name
|
|
@add name, 'var'
|
|
no
|
|
|
|
Reserve a variable name as originating from a function parameter for this
|
|
scope. No `var` required for internal references.
|
|
|
|
parameter: (name) ->
|
|
return if @shared and @parent.check name, yes
|
|
@add name, 'param'
|
|
|
|
Just check to see if a variable has already been declared, without reserving,
|
|
walks up to the root scope.
|
|
|
|
check: (name) ->
|
|
!!(@type(name) or @parent?.check(name))
|
|
|
|
Generate a temporary variable name at the given index.
|
|
|
|
temporary: (name, index) ->
|
|
if name.length > 1
|
|
'_' + name + if index > 1 then index - 1 else ''
|
|
else
|
|
'_' + (index + parseInt name, 36).toString(36).replace /\d/g, 'a'
|
|
|
|
Gets the type of a variable.
|
|
|
|
type: (name) ->
|
|
return v.type for v in @variables when v.name is name
|
|
null
|
|
|
|
If we need to store an intermediate result, find an available name for a
|
|
compiler-generated variable. `_var`, `_var2`, and so on...
|
|
|
|
freeVariable: (name, reserve=true) ->
|
|
index = 0
|
|
index++ while @check((temp = @temporary name, index))
|
|
@add temp, 'var', yes if reserve
|
|
temp
|
|
|
|
Ensure that an assignment is made at the top of this scope
|
|
(or at the top-level scope, if requested).
|
|
|
|
assign: (name, value) ->
|
|
@add name, {value, assigned: yes}, yes
|
|
@hasAssignments = yes
|
|
|
|
Does this scope have any declared variables?
|
|
|
|
hasDeclarations: ->
|
|
!!@declaredVariables().length
|
|
|
|
Return the list of variables first declared in this scope.
|
|
|
|
declaredVariables: ->
|
|
realVars = []
|
|
tempVars = []
|
|
for v in @variables when v.type is 'var'
|
|
(if v.name.charAt(0) is '_' then tempVars else realVars).push v.name
|
|
realVars.sort().concat tempVars.sort()
|
|
|
|
Return the list of assignments that are supposed to be made at the top
|
|
of this scope.
|
|
|
|
assignedVariables: ->
|
|
"#{v.name} = #{v.type.value}" for v in @variables when v.type.assigned
|
|
|