Add support for parsing default arguments and storing them in the par…

…se tree
vidarh · Apr 10, 2014 · 7bca9f3 · 7bca9f3
1 parent c9e5162
commit 7bca9f3
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Showing 3 changed files with 18 additions and 15 deletions.
diff --git a/features/parser.feature b/features/parser.feature
@@ -95,17 +95,17 @@ Feature: Parser
         Then the parse tree should become <tree>
 
     Examples:
-      | expr                             | tree                                         | notes                                               |
-      | "def foo(bar=nil); end"          | [:do, [:defm, :foo, [:bar], []]]             | Default value for arguments                         |
-      | "def foo(bar = nil); end"        | [:do, [:defm, :foo, [:bar], []]]             | Default value for arguments - with whitespace       |
-      | "def foo(bar = []); end"         | [:do, [:defm, :foo, [:bar], []]]             | Default value for arguments - with whitespace       |
-      | "def foo(&bar);end  "            | [:do, [:defm, :foo, [[:bar,:block]], []]]    | Block as named argument                             |
-      | "def foo(a = :b, c = :d);end;  " | [:do, [:defm, :foo, [:a,:c], []]]            | Second argument following argument with initializer |
-      | "def foo(a = :b, &bar);end;  "   | [:do, [:defm, :foo, [:a,[:bar,:block]], []]] | Second argument following argument with initializer |
-      | "def self.foo;end;"              | [:do, [:defm, [:self,:foo], [], []]]         | Class method etc.                                   |
-      | "def *(other_array); end;"       | [:do, [:defm, :*, [:other_array], []]]       | *-Operator overloading                              |
-      | "def foo=(bar);end;"             | [:do, [:defm, :foo=, [:bar], []]]            | setter                                              |
-      | "def == bar; end"                | [:do, [:defm, :==, [:bar], []]]              | Handle operator method name                         |
+      | expr                             | tree                                                                   | notes                                               |
+      | "def foo(bar=nil); end"          | [:do, [:defm, :foo, [[:bar, :default, :nil]], []]]                     | Default value for arguments                         |
+      | "def foo(bar = nil); end"        | [:do, [:defm, :foo, [[:bar, :default, :nil]], []]]                     | Default value for arguments - with whitespace       |
+      | "def foo(bar = []); end"         | [:do, [:defm, :foo, [[:bar, :default, [:array]]], []]]                 | Default value for arguments - with whitespace       |
+      | "def foo(&bar);end  "            | [:do, [:defm, :foo, [[:bar,:block]], []]]                              | Block as named argument                             |
+      | "def foo(a = :b, c = :d);end;  " | [:do, [:defm, :foo, [[:a,:default, :":b"],[:c,:default, :":d"]], []]]  | Second argument following argument with initializer |
+      | "def foo(a = :b, &bar);end;  "   | [:do, [:defm, :foo, [[:a,:default, :":b"],[:bar,:block]], []]]         | Second argument following argument with initializer |
+      | "def self.foo;end;"              | [:do, [:defm, [:self,:foo], [], []]]                                   | Class method etc.                                   |
+      | "def *(other_array); end;"       | [:do, [:defm, :*, [:other_array], []]]                                 | *-Operator overloading                              |
+      | "def foo=(bar);end;"             | [:do, [:defm, :foo=, [:bar], []]]                                      | setter                                              |
+      | "def == bar; end"                | [:do, [:defm, :==, [:bar], []]]                                        | Handle operator method name                         |
 
     @class
     Scenario Outline: Classes

diff --git a/parser.rb b/parser.rb
@@ -29,14 +29,17 @@ def parse_arglist
     end
 
     nolfws
+    default = nil
     if expect("=")
       nolfws
-      @shunting.parse([","])
-      # FIXME: Store
+      default = @shunting.parse([","])
     end
 
     if prefix then args = [[name.to_sym, prefix == "*" ? :rest : :block]]
-    else args = [name.to_sym]
+    elsif default
+      args = [[name.to_sym, :default, default]]
+    else 
+      args = [name.to_sym]
     end
     nolfws
     expect(",") or return args

diff --git a/transform.rb b/transform.rb
@@ -204,7 +204,7 @@ def rewrite_env_vars(exp, env)
 
   def rewrite_let_env(exp)
     exp.depth_first(:defm) do |e|
-      args   = Set[*e[2]]
+      args   = Set[*e[2].collect{|a| a.kind_of?(Array) ? a[0] : a}]
       scopes = [args.dup] # We don't want "args" above to get updated 
 
       # We use this to assign registers