Simplifying the control flow API and deduplicating the code.

1 files changed, 27 insertions, 98 deletions

diff --git a/core/control_flow.nom b/core/control_flow.nom
index f01d948..4fe94e4 100644
--- a/core/control_flow.nom
+++ b/core/control_flow.nom
@@ -87,29 +87,29 @@ test:
     assume (%i == 0)
 
 (--- %label ---) compiles to "\
-    ..::label_\((%label.stub if (%label.type == "Action") else %label) as lua identifier)::"
+    ..::label_\((%label.stub::as lua id) if (%label.type == "Action") else (%label as lua identifier))::"
 
 (go to %label) compiles to "\
-    ..goto label_\((%label.stub if (%label.type == "Action") else %label) as lua identifier)"
+    ..goto label_\((%label.stub::as lua id) if (%label.type == "Action") else (%label as lua identifier))"
 
 # Basic loop control
 (stop %var) compiles to:
     if %var:
-        return (Lua "goto stop_\((%var.stub if (%var.type == "action") else %var) as lua identifier)")
+        return (Lua "goto stop_\(%var as lua identifier)")
     ..else:
         return (Lua "break")
 
 (do next %var) compiles to:
     if %var:
-        return (Lua "goto continue_\((%var.stub if (%var.type == "action") else %var) as lua identifier)")
+        return (Lua "goto continue_\(%var as lua identifier)")
     ..else:
         return (Lua "goto continue")
 
 (---stop %var ---) compiles to "\
-    ..::stop_\((%var.stub if (%var.type == "action") else %var) as lua identifier)::"
+    ..::stop_\(%var as lua identifier)::"
 
 (---next %var ---) compiles to "\
-    ..::continue_\((%var.stub if (%var.type == "action") else %var) as lua identifier)::"
+    ..::continue_\(%var as lua identifier)::"
 
 # While loops
 test:
@@ -117,8 +117,6 @@ test:
     repeat while (%x < 10): %x += 1
     assume (%x == 10)
     repeat while (%x < 20): stop
-    repeat while (%x < 20):
-        stop repeating
     assume (%x == 10)
     repeat while (%x < 20):
         %x += 1
@@ -126,57 +124,14 @@ test:
             do next
         barf "Failed to 'do next'"
     assume (%x == 20)
-    repeat while (%x < 30):
-        %x += 1
-        if (yes):
-            do next repeat
-        barf "Failed to 'do next repeat'"
-    assume (%x == 30)
-(do next repeat) compiles to "goto continue_repeat"
-(stop repeating) compiles to "goto stop_repeat"
 (repeat while %condition %body) compiles to:
     %lua = (Lua "while \(%condition as lua expr) do\n    \(%body as lua)")
     if (%body has subtree \(do next)):
         %lua::append "\n    ::continue::"
-    
-    if (%body has subtree \(do next repeat)):
-        %lua::append "\n    ::continue_repeat::"
-    
     %lua::append "\nend --while-loop"
-    if (%body has subtree \(stop repeating)):
-        %inner_lua = %lua
-        %lua = (Lua "do -- scope of 'stop repeating' label\n    ")
-        %lua::append %inner_lua "\
-            ..
-                ::stop_repeat::
-            end -- end of 'stop repeating' label scope"
     return %lua
 (repeat %body) parses as (repeat while (yes) %body)
 (repeat until %condition %body) parses as (repeat while (not %condition) %body)
-test:
-    %x = 0
-    repeat 10 times: %x += 1
-    assume (%x == 10)
-
-(repeat %n times %body) compiles to:
-    define mangler
-    %lua = (Lua "for \(mangle "i")=1,\(%n as lua expr) do\n    ")
-    %lua::append (%body as lua)
-    if (%body has subtree \(do next)):
-        %lua::append "\n    ::continue::"
-    
-    if (%body has subtree \(do next repeat)):
-        %lua::append "\n    ::continue_repeat::"
-    
-    %lua::append "\nend --numeric for-loop"
-    if (%body has subtree \(stop repeating)):
-        %inner_lua = %lua
-        %lua = (Lua "do -- scope of 'stop repeating' label\n    ")
-        %lua::append %inner_lua "\
-            ..
-                ::stop_repeat::
-            end -- end of 'stop repeating' label scope"
-    return %lua
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -206,22 +161,20 @@ test:
     for %var in %start to %stop via %step %body
 ..all compile to:
     # This uses Lua's approach of only allowing loop-scoped variables in a loop
-    unless (%var.type is "Var"):
-        compile error at %var "Expected a variable here, not a \(%var.type)"
-    %lua = (Lua "for \(%var as lua expr)=\(%start as lua expr),\(%stop as lua expr),\(%step as lua expr) do")
+    %lua = (Lua "for \(%var as lua identifier)=\(%start as lua expr),\(%stop as lua expr),\(%step as lua expr) do")
     %lua::append "\n    " (%body as lua)
     if (%body has subtree \(do next)):
         %lua::append "\n    ::continue::"
     
     if (%body has subtree \(do next %var)):
-        %lua::append "\n    " (what (---next %var ---) compiles to)
+        %lua::append "\n    " (\(---next %var ---) as lua)
     
     %lua::append "\nend --numeric for-loop"
     if (%body has subtree \(stop %var)):
         %inner_lua = %lua
         %lua = (Lua "do -- scope for stopping for-loop\n    ")
         %lua::append %inner_lua "\n    "
-        %lua::append (what (---stop %var ---) compiles to)
+        %lua::append (\(---stop %var ---) as lua)
         %lua::append "\nend -- end of scope for stopping for-loop"
     return %lua
 
@@ -231,6 +184,12 @@ test:
     for %var in %start to %stop via 1 %body
 
 test:
+    %x = 0
+    repeat 5 times: %x += 1
+    assume %x == 5
+(repeat %n times %body) parses as (for (=lua "_XXX_") in 1 to %n %body)
+
+test:
     %a = [10, 20, 30, 40, 50]
     %b = []
     for %x in %a:
@@ -248,31 +207,6 @@ test:
     assume (%b == [20, 30, 40])
 
 # For-each loop (lua's "ipairs()")
-(for %var in %iterable %body) compiles to:
-    define mangler
-    
-    # This uses Lua's approach of only allowing loop-scoped variables in a loop
-    %lua = (..)
-        Lua "\
-            ..for \(mangle "i"),\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do
-                "
-    %lua::append (%body as lua)
-    if (%body has subtree \(do next)):
-        %lua::append "\n    ::continue::"
-    
-    if (%body has subtree \(do next %var)):
-        %lua::append "\n    " (what (---next %var ---) compiles to)
-    
-    %lua::append "\nend --foreach-loop"
-    if (%body has subtree \(stop %var)):
-        %inner_lua = %lua
-        %lua = (Lua "do -- scope for stopping for-loop\n    ")
-        %lua::append %inner_lua "\n    "
-        %lua::append (what (---stop %var ---) compiles to)
-        %lua::append "\nend -- end of scope for stopping for-loop"
-    return %lua
-
-# TODO: reduce code duplication
 (for %var in %iterable at %i %body) compiles to:
     # This uses Lua's approach of only allowing loop-scoped variables in a loop
     %lua = (..)
@@ -284,17 +218,19 @@ test:
         %lua::append "\n    ::continue::"
     
     if (%body has subtree \(do next %var)):
-        %lua::append "\n    " (what (---next %var ---) compiles to)
+        %lua::append "\n    " (\(---next %var ---) as lua)
     
-    %lua::append "\nend --foreach-loop"
+    %lua::append "\nend --for \(%var as lua identifier) loop"
     if (%body has subtree \(stop %var)):
         %inner_lua = %lua
         %lua = (Lua "do -- scope for stopping for-loop\n    ")
         %lua::append %inner_lua "\n    "
-        %lua::append (what (---stop %var ---) compiles to)
+        %lua::append (\(---stop %var ---) as lua)
         %lua::append "\nend -- end of scope for stopping for-loop"
     return %lua
 
+(for %var in %iterable %body) parses as (for %var in %iterable at (=lua "__") %body)
+
 test:
     %d = {a: 10, b: 20, c: 30, d: 40, e: 50}
     %result = []
@@ -311,31 +247,24 @@ test:
 # Dict iteration (lua's "pairs()")
 [for %key = %value in %iterable %body, for %key %value in %iterable %body] \
 ..all compile to:
-    # This uses Lua's approach of only allowing loop-scoped variables in a loop
-    unless (%key.type is "Var"):
-        compile error at %key "Expected a variable here, not a \(%key.type)"
-    
-    unless (%value.type is "Var"):
-        compile error at %value "Expected a variable here, not a \(%value.type)"
-    
     %lua = (Lua "for \(%key as lua identifier),\(%value as lua identifier) in pairs(\(%iterable as lua expr)) do")
     %lua::append "\n    " (%body as lua)
     if (%body has subtree \(do next)):
         %lua::append "\n    ::continue::"
     
     if (%body has subtree \(do next %key)):
-        %lua::append "\n    " (what (---next %key ---) compiles to)
+        %lua::append "\n    " (\(---next %key ---) as lua)
     
     if (%body has subtree \(do next %value)):
-        %lua::append "\n    " (what (---next %value ---) compiles to)
+        %lua::append "\n    " (\(---next %value ---) as lua)
     
     %lua::append "\nend --foreach-loop"
     %stop_labels = (Lua "")
     if (%body has subtree \(stop %key)):
-        %stop_labels::append "\n" (what (---stop %key ---) compiles to)
+        %stop_labels::append "\n" (\(---stop %key ---) as lua)
     
     if (%body has subtree \(stop %value)):
-        %stop_labels::append "\n" (what (---stop %value ---) compiles to)
+        %stop_labels::append "\n" (\(---stop %value ---) as lua)
     
     if ((size of "\%stop_labels") > 0):
         %inner_lua = %lua
@@ -506,7 +435,7 @@ test:
     assume ((result of: return 99) == 99)
 
 # Inline thunk:
-(result of %body) compiles to "\(what (-> %body) compiles to)()"
+(result of %body) compiles to "\(\(-> %body) as lua)()"
 test:
     %t = [1, [2, [[3], 4], 5, [[[6]]]]]
     %flat = []
@@ -537,10 +466,10 @@ test:
             %lua::append "\n        ::continue::"
         
         if (%body has subtree \(do next %var)):
-            %lua::append "\n        \(what (---next %var ---) compiles to)"
+            %lua::append "\n        \(\(---next %var ---) as lua)"
         
         %lua::append "\n    end -- Recursive loop"
         if (%body has subtree \(stop %var)):
-            %lua::append "\n        \(what (---stop %var ---) compiles to)"
+            %lua::append "\n        \(\(---stop %var ---) as lua)"
         %lua::append "\nend -- Recursive scope"
         return %lua