Add 'Flow' to represent control-flow constructs.

src/Data/Reprinting/Token.hs

@@ -4,6 +4,7 @@ module Data.Reprinting.Token
   , isControl
   , Element (..)
   , Control (..)
+  , Flow (..)
   ) where
 
 import Data.Text (Text)
@@ -36,10 +37,33 @@ data Element
   | Nullity          -- ^ @null@ or @nil@ or some other zero value.
   | Sep              -- ^ Some sort of delimiter, interpreted in some 'Context'.
   | Sym              -- ^ Some sort of symbol, interpreted in some 'Context'.
-  | Then
-  | Else
   | Open             -- ^ The beginning of some 'Context', such as an @[@ or @{@.
-  | Close      -- ^ The opposite of 'TOpen'.
+  | Close            -- ^ The opposite of 'Open'.
+  | Access           -- ^ Member/method access
+  | Resolve          -- ^ Namespace/package resolution
+  | Assign           -- ^ Variable binding
+  | Self             -- ^ @self@ or @this@
+  | Superclass       -- ^ @super@
+  | Flow Flow        -- ^ Control-flow token (@if@, @else@, @for@...)
+  | Extends          -- ^ Subclassing indicator (syntax varies)
+    deriving (Eq, Show)
+
+-- | Helper datum to corral control-flow entities like @while@, @for@,
+-- etc. Usually corresponds to a keyword in a given language.
+data Flow
+  = Break
+  | Continue
+  | Else
+  | For
+  | Foreach
+  | In     -- ^ Usually associated with 'Foreach' loops
+  | Rescue -- ^ AKA @catch@ in most languages
+  | Retry
+  | Switch -- ^ AKA @case@
+  | Then   -- ^ The true-branch of @if@-statements
+  | Try
+  | While
+  | Yield
     deriving (Eq, Show)
 
 -- | 'Control' tokens describe information about some AST's context.

src/Data/Syntax/Statement.hs

@@ -14,7 +14,7 @@ import Data.Abstract.Evaluatable as Abstract
 import Control.Abstract.ScopeGraph
 import Data.JSON.Fields
 import Diffing.Algorithm
-import Reprinting.Tokenize
+import Reprinting.Tokenize (Tokenize (..), imperative, within', yield)
 import qualified Data.Reprinting.Token as Token
 import qualified Data.Reprinting.Scope as Scope
 
@@ -57,9 +57,9 @@ instance Evaluatable If where
 instance Tokenize If where
   tokenize If{..} = within' Scope.If $ do
     ifCondition
-    yield Token.Then
+    yield (Token.Flow Token.Then)
     ifThenBody
-    yield Token.Else
+    yield (Token.Flow Token.Else)
     ifElseBody
 
 -- | Else statement. The else condition is any term, that upon successful completion, continues evaluation to the elseBody, e.g. `for ... else` in Python.

src/Language/Python/PrettyPrint.hs

@@ -36,8 +36,8 @@ step (Defer el cs)  = case (el, cs) of
 
   -- If statements
   (Open,       If:_)           -> emit "if" *> space
-  (Then,  If:_)                -> emit ":"
-  (Else,  If:xs)               -> endContext (imperativeDepth xs) *> emit "else:"
+  (Flow Then,  If:_)           -> emit ":"
+  (Flow Else,  If:xs)          -> endContext (imperativeDepth xs) *> emit "else:"
   (Close,      If:_)           -> pure ()
 
   -- Booleans