Switch statements

compiler/codegen.rb

@@ -20,17 +20,24 @@ def generate(node)
       ]
 
     when IfNode
-      body_code = 
-      if node.body.is_a?(Array)
-        node.body.map { |n| generate (n) }.join("\n")
-      else
-        generate(node.body)
+      compiled = ""
+
+      first = node.condition
+      compiled << "if #{generate(first)} then\n"
+      compiled << node.body.map { |n| generate (n) }.join("\n")
+
+      node.elif_blocks.each do |c|
+        compiled << "\nelseif #{generate(c.condition)} then\n"
+        compiled << c.body.map { |n| generate (n) }.join("\n")
       end
 
-      "if %s then \n %s \nend" % [
-        generate(node.statement),
-        body_code
-      ]
+      if node.else_body
+        compiled << "\nelse\n"
+        compiled << node.else_body.map { |n| generate (n) }.join("\n")
+      end
+
+      compiled << "\nend"
+      compiled
 
     when WhileNode
       body_code = 
@@ -44,6 +51,24 @@ def generate(node)
         generate(node.statement),
         body_code
       ]
+
+    when SwitchNode
+      compiled = ""
+      node.cases.each_with_index do |c, i|
+        if i == 0
+          compiled << "if #{generate(c.match)} == #{generate(node.value)} then\n"
+        else
+          compiled << "elseif #{generate(c.match)} == #{generate(node.value)} then\n"
+        end
+
+        body_code = c.body.map { |b| generate(b) }.join("\n")
+        compiled << " #{body_code}\n"
+
+      end
+      compiled << "end"
+      compiled
+
+
     when CallNode
       "%s(%s)" % [
         node.name,

compiler/parser.rb

@@ -1,5 +1,8 @@
 DefNode  = Struct.new(:name, :args, :body)
-IfNode = Struct.new(:statement, :body)
+
+IfNode = Struct.new(:condition, :body, :elif_blocks, :else_body)
+ElifBlock = Struct.new(:condition, :body)
+
 WhileNode = Struct.new(:statement, :body)
 IntegerNode = Struct.new(:value)
 StringNode = Struct.new(:value)
@@ -11,6 +14,8 @@
 PrintNode = Struct.new(:args)
 ReturnNode = Struct.new(:statement)
 AndOrListNode = Struct.new(:items)
+SwitchNode = Struct.new(:value, :cases)
+CaseNode = Struct.new(:match, :body)
 
 LoveCallNode = Struct.new(:namespace, :name, :args)
 
@@ -86,26 +91,71 @@ def parse_return
   end
 
   def parse_if
+
     consume(:if)
+    condition = parse_expr
+    skip_newlines
+    if_body = []
+    while !peek(:elif) && !peek(:else) && !peek(:end)
+      if_body << parse_statement
+      skip_newlines
+    end
+
+
+    elif_blocks = []
+    while peek(:elif)
+      consume(:elif)
+      elif_condition = parse_expr
+      skip_newlines
+
+      elif_body = []
+      while !peek(:elif) && !peek(:else) && !peek(:end)
+        elif_body << parse_statement
+        skip_newlines
+      end
+
+      elif_blocks << ElifBlock.new(elif_condition, elif_body)
 
-    if peek(:oparen)
-      consume(:oparen)
-      statement = parse_expr
-      consume(:cparen)
-    else
-      statement = parse_expr
     end
-    skip_newlines
-    body = []
 
-    until peek(:end)
-      body << parse_statement
+    else_body = nil
+    if peek(:else)
+      consume(:else)
       skip_newlines
+
+      else_body = []
+      while !peek(:end)
+        else_body << parse_statement
+        skip_newlines
+      end
     end
+
     consume(:end)
-    IfNode.new(statement, body)
+
+    IfNode.new(condition, if_body, elif_blocks, else_body)
+
+
   end
 
+    # consume(:if)
+
+    # if peek(:oparen)
+    #   consume(:oparen)
+    #   statement = parse_expr
+    #   consume(:cparen)
+    # else
+    #   statement = parse_expr
+    # end
+    # skip_newlines
+    # body = []
+
+    # until peek(:elif) peek(:end)
+    #   body << parse_statement
+    #   skip_newlines
+    # end
+    # consume(:end)
+    # IfNode.new(statement, body)
+
   def parse_while
     consume(:while)
 
@@ -129,6 +179,32 @@ def parse_while
     WhileNode.new(statement, body)
   end
 
+  def parse_switch
+    consume(:switch)
+    value = parse_expr
+    skip_newlines
+
+    cases = []
+
+    while peek(:to)
+      consume(:to)
+      match = parse_expr
+      skip_newlines
+
+      body = []
+
+      until peek(:to) || peek(:end)
+        body << parse_statement
+        skip_newlines
+      end
+
+      cases << CaseNode.new(match, body)
+    end
+
+    consume(:end)
+    SwitchNode.new(value, cases)
+  end
+
 
   def parse_print
     consume(:print)
@@ -148,6 +224,8 @@ def parse_statement
       parse_if
     elsif peek(:while)
       parse_while
+    elsif peek(:switch)
+      parse_switch
     elsif peek(:print)
       parse_print
     elsif peek(:local)

compiler/tokenizer.rb

@@ -7,11 +7,15 @@ class Tokenizer
     [:def, /\bcall\b/],
     [:end, /\bdone\b/],
     [:if, /\bif\b/],
+    [:elif, /\belif\b/],
+    [:else, /\belse\b/],
     [:while, /\bwhen\b/],
     [:print, /\bprint\b/],
     [:return, /\breturn\b/],
     [:or, /\bor\b/],
     [:and, /\band\b/],
+    [:switch, /\bswitch\b/],
+    [:to, /\bto\b/],
 
     #love 
     [:lgraphics, /-G:/],
@@ -38,7 +42,7 @@ class Tokenizer
     [:greater, />/],
     [:lesser, /</],
     [:grequal, />=/],
-    [:lequal, /<=/]
+    [:lequal, /<=/],
     [:equal, /=/],
     [:divide, /\//],
     [:multiply, /\*/],

examples/main.lat

@@ -4,6 +4,8 @@ nat multiplier = 2
 
 if (-K:isDown("space"))
     incrementCoin(3)
+elif (-K:isDown("w"))
+    incrementCoin(3)
 done
 
 
@@ -16,5 +18,13 @@ when (true)
 
 done
 
+switch score 
+    to 10
+        print("perfect")
+    to 5
+        print("ok")
+
+done
+
 
 print(coins)

test.lua

@@ -1,14 +1,21 @@
 local coins = 250
 local incrementVal = 20
 local multiplier = 2
-if love.keyboard.isDown("space") then 
- incrementCoin(3) 
+if love.keyboard.isDown("space") then
+incrementCoin(3)
+elseif love.keyboard.isDown("w") then
+incrementCoin(3)
 end
 function incrementCoin(externalMultiplier)
   coins = (coins + ((incrementVal * multiplier) * externalMultiplier))
   return coins 
 end
 while true do 
 
+end
+if 10 == score then
+ print("perfect")
+elseif 5 == score then
+ print("ok")
 end
 print(coins)