first draft of array comprehensions, but they stink.

code.jaa

@@ -1,5 +1,8 @@
 # TODO: switch/case statements
-# Flow: For loops, while loops, etc.
+# Flow: For loops, etc.
+# ++ and -- (prefix and postfix)
+# postfix ifs and unlesses
+# Fix array comprehensions -- they're mad busted.
 
 # Functions:
 square: x => x * x.
@@ -66,4 +69,20 @@ catch error
 finally
   clean_up().
 
-try all_hell_breaks_loose() catch error print(error) finally clean_up().
+try all_hell_breaks_loose() catch error print(error) finally clean_up().
+
+# While loops.
+while demand > supply
+  sell()
+  restock().
+
+while supply > demand then buy().
+
+# Unary operators.
+!!true
+
+# For loops.
+foods: ['toast', 'wine', 'cheese']
+print(item.capitalize()) for item in foods.
+
+drink(item) for item in foods if item is 'wine'.

grammar.y

@@ -8,6 +8,7 @@ token IDENTIFIER PROPERTY_ACCESS
 token CODE PARAM NEW RETURN
 token TRY CATCH FINALLY THROW
 token BREAK CONTINUE
+token FOR IN WHILE
 token NEWLINE
 
 prechigh
@@ -59,6 +60,8 @@ rule
   | Try
   | Throw
   | Return
+  | While
+  | For
   ;
 
   # All tokens that can terminate an expression
@@ -67,6 +70,12 @@ rule
   | ";"
   ;
 
+  # All tokens that can serve to begin the second block
+  Then:
+    THEN
+  | Terminator
+  ;
+
   # All hard-coded values
   Literal:
     NUMBER                            { result = LiteralNode.new(val[0]) }
@@ -164,11 +173,18 @@ rule
   ;
 
   Object:
-    "{" "}"                           { result = ObjectNode.new([]) }
-  | "{" Terminator "}"                { result = ObjectNode.new([]) }
-  | "{" AssignList "}"                { result = ObjectNode.new(val[1]) }
-  | "{" Terminator AssignList
-        Terminator "}"                { result = ObjectNode.new(val[2]) }
+    ObjectStart ObjectEnd             { result = ObjectNode.new([]) }
+  | ObjectStart AssignList ObjectEnd  { result = ObjectNode.new(val[1]) }
+  ;
+
+  ObjectStart:
+    "{"                               { result = nil }
+  | "{" "\n"                          { result = nil }
+  ;
+
+  ObjectEnd:
+    "}"                               { result = nil }
+  | "\n" "}"                          { result = nil }
   ;
 
   AssignList:
@@ -185,7 +201,7 @@ rule
   ;
 
   Invocation:
-    Value "(" ArgList ")"          { result = CallNode.new(val[0], val[2]) }
+    Value "(" ArgList ")"             { result = CallNode.new(val[0], val[2]) }
   ;
 
   # An Array.
@@ -203,15 +219,10 @@ rule
 
   If:
     IF Expression
-       THEN Expression "."            { result = IfNode.new(val[1], val[3]) }
-  | IF Expression Terminator
-       Expressions "."                { result = IfNode.new(val[1], val[3]) }
+       Then Expressions "."           { result = IfNode.new(val[1], val[3]) }
   | IF Expression
-       THEN Expression
-       ELSE Expression "."            { result = IfNode.new(val[1], val[3], val[5]) }
-  | IF Expression Terminator
-       Expressions Terminator
-       ELSE Expressions "."           { result = IfNode.new(val[1], val[3], val[6]) }
+       Then Expressions
+       ELSE Expressions "."           { result = IfNode.new(val[1], val[3], val[5]) }
   ;
 
   Try:
@@ -232,6 +243,19 @@ rule
     "(" Expressions ")"               { result = ParentheticalNode.new(val[1]) }
   ;
 
+  While:
+    WHILE Expression Then
+      Expressions "."                 { result = WhileNode.new(val[1], val[3]) }
+  ;
+
+  For:
+    Expression FOR IDENTIFIER
+      IN Expression "."               { result = ForNode.new(val[0], val[2], val[4]) }
+  | Expression FOR IDENTIFIER
+      IN Expression
+      IF Expression "."               { result = ForNode.new(IfNode.new(val[6], Nodes.new([val[0]])), val[2], val[4]) }
+  ;
+
 end
 
 ---- header

lexer.rb

@@ -5,7 +5,8 @@ class Lexer
                 "and", "or", "is", "aint", "not",
                 "new", "return",
                 "try", "catch", "finally", "throw",
-                "break", "continue"]
+                "break", "continue",
+                "for", "in", "while"]
 
   IDENTIFIER = /\A([a-zA-Z$_]\w*)/
   NUMBER     = /\A([0-9]+(\.[0-9]+)?)/

nodes.rb

@@ -17,6 +17,11 @@ end
 # Collection of nodes each one representing an expression.
 class Nodes < Node
   attr_reader :nodes
+
+  def self.wrap(node)
+    node.is_a?(Nodes) ? node : Nodes.new([node])
+  end
+
   def initialize(nodes)
     @nodes = nodes
   end
@@ -26,10 +31,12 @@ class Nodes < Node
     self
   end
 
-  #   line  = node.compile(indent + TAB, {:last => last})
-  #   line  = "return #{line}" if last
-  #   indent + TAB + line + node.line_ending
+  def flatten
+    @nodes.length == 1 ? @nodes.first : self
+  end
 
+  # Fancy to handle pushing down returns recursively to the final lines of
+  # inner statements (to make expressions out of them).
   def compile(indent='', opts={})
     @nodes.map { |n|
       if opts[:return] && n == @nodes.last
@@ -63,7 +70,7 @@ class ReturnNode < Node
   end
 
   def compile(indent, opts={})
-    "#{indent}return #{@expression.compile(indent)};"
+    "return #{@expression.compile(indent)}"
   end
 end
 
@@ -170,6 +177,7 @@ class OpNode < Node
 
   def compile(indent, opts={})
     return compile_conditional(indent) if CONDITIONALS.include?(@operator)
+    return compile_unary(indent) if unary?
     op = "#{@first.compile(indent)} #{@operator} #{@second.compile(indent)}"
     opts[:no_paren] ? op : "(#{op})"
   end
@@ -179,6 +187,10 @@ class OpNode < Node
     sym = @operator[0..1]
     "(#{first} = #{first} #{sym} #{second})"
   end
+
+  def compile_unary(indent)
+    "#{@operator}#{@first.compile(indent)}"
+  end
 end
 
 # Method definition.
@@ -229,7 +241,9 @@ class IfNode < Node
   FORCE_STATEMENT = [Nodes, ReturnNode]
 
   def initialize(condition, body, else_body=nil)
-    @condition, @body, @else_body = condition, body, else_body
+    @condition = condition
+    @body      = body && body.flatten
+    @else_body = else_body && else_body.flatten
   end
 
   def statement?
@@ -245,8 +259,8 @@ class IfNode < Node
   end
 
   def compile_statement(indent, opts)
-    if_part   = "if (#{@condition.compile(indent, :no_paren => true)}) {\n#{@body.compile(indent + TAB, opts)}\n#{indent}}"
-    else_part = @else_body ? " else {\n#{@else_body.compile(indent + TAB, opts)}\n#{indent}}" : ''
+    if_part   = "if (#{@condition.compile(indent, :no_paren => true)}) {\n#{Nodes.wrap(@body).compile(indent + TAB, opts)}\n#{indent}}"
+    else_part = @else_body ? " else {\n#{Nodes.wrap(@else_body).compile(indent + TAB, opts)}\n#{indent}}" : ''
     if_part + else_part
   end
 
@@ -257,6 +271,49 @@ class IfNode < Node
   end
 end
 
+class WhileNode < Node
+  def initialize(condition, body)
+    @condition, @body = condition, body
+  end
+
+  def line_ending
+    ''
+  end
+
+  def statement?
+    true
+  end
+
+  def compile(indent, opts={})
+    "while (#{@condition.compile(indent, :no_paren => true)}) {\n#{@body.compile(indent + TAB)}\n#{indent}}"
+  end
+end
+
+class ForNode < Node
+  I = "__i__"
+  L = "__l__"
+  S = "__s__"
+
+  def initialize(body, name, source, condition=nil)
+    @body, @name, @source, @condition = body, name, source, condition
+  end
+
+  def line_ending
+    ''
+  end
+
+  def statement?
+    true
+  end
+
+  def compile(indent, opts={})
+    source_part = "var #{S} = #{@source.compile(indent)};"
+    for_part = "var #{I}=0, #{L}=#{S}.length; #{I}<#{L}; #{I}++"
+    var_part = "\n#{indent + TAB}var #{@name} = #{S}[#{I}];"
+    "#{source_part}\n#{indent}for (#{for_part}) {#{var_part}\n#{indent + TAB}#{@body.compile(indent + TAB)};\n#{indent}}"
+  end
+end
+
 class TryNode < Node
   def initialize(try, error, recovery, finally=nil)
     @try, @error, @recovery, @finally = try, error, recovery, finally