Support for conditonal expression (if-expression) - review findings

ASTree.cpp

@@ -30,7 +30,7 @@ static bool printDocstringAndGlobals = false;
 static bool printClassDocstring = true;
 
 // shortcut for all top/pop calls
-PycRef<ASTNode> StackPopTop(FastStack& stack)
+static PycRef<ASTNode> StackPopTop(FastStack& stack)
 {
     const auto node{ stack.top() };
     stack.pop();
@@ -47,7 +47,7 @@ PycRef<ASTNode> StackPopTop(FastStack& stack)
  *  here, try to guess if just finished else statement is part of if-expression (ternary operator)
  *  if it is, remove statements from the block and put a ternary node on top of stack
  */
-void CheckIfExpr(FastStack& stack, PycRef<ASTBlock> curblock)
+static void CheckIfExpr(FastStack& stack, PycRef<ASTBlock> curblock)
 {
     if (stack.empty())
         return;
@@ -3287,13 +3287,16 @@ void print_src(PycRef<ASTNode> node, PycModule* mod)
         break;
     case ASTNode::NODE_TERNARY:
         {
-            /* parenthesis might not be needed,
-             * but when if-expr is part of numerical expression, ternary has the LOWEST precedence
+            /* parenthesis might be needed
+             * 
+             * when if-expr is part of numerical expression, ternary has the LOWEST precedence
              *     print(a + b if False else c)
              * output is c, not a+c (a+b is calculated first)
+             * 
+             * but, let's not add parenthesis - to keep the source as close to original as possible in most cases
              */
             PycRef<ASTTernary> ternary = node.cast<ASTTernary>();
-            fputs("( ", pyc_output);
+            //fputs("(", pyc_output);
             print_src(ternary->if_expr(), mod);
             const auto if_block = ternary->if_block().require_cast<ASTCondBlock>();
             fputs(" if ", pyc_output);
@@ -3302,7 +3305,7 @@ void print_src(PycRef<ASTNode> node, PycModule* mod)
             print_src(if_block->cond(), mod);
             fputs(" else ", pyc_output);
             print_src(ternary->else_expr(), mod);
-            fputs(" )", pyc_output);
+            //fputs(")", pyc_output);
         }
         break;
     default:

tests/input/conditional_expressions.py

@@ -0,0 +1,42 @@
+a = 1
+result = 'even' if a % 2 == 0 else 'odd'
+print(result)
+# odd
+
+a = 2
+result = 'even' if a % 2 == 0 else 'odd'
+print(result)
+# even
+
+a = 1
+result = a * 2 if a % 2 == 0 else a * 3
+print(result)
+# 3
+
+a = 2
+result = a * 2 if a % 2 == 0 else a * 3
+print(result)
+# 4
+
+a = 1
+print('even') if a % 2 == 0 else print('odd')
+# odd
+
+a = 1
+
+if a % 2 == 0:
+    print('even')
+else:
+    print('odd')
+# odd
+
+a = -2
+result = 'negative and even' if a < 0 and a % 2 == 0 else 'positive or odd'
+print(result)
+# negative and even
+
+a = -1
+result = 'negative and even' if a < 0 and a % 2 == 0 else 'positive or odd'
+print(result)
+# positive or odd
+

tests/tokenized/conditional_expressions.txt

@@ -0,0 +1,29 @@
+a = 1 <EOL>
+result = 'even' if a % 2 == 0 else 'odd' <EOL>
+print ( result ) <EOL>
+a = 2 <EOL>
+result = 'even' if a % 2 == 0 else 'odd' <EOL>
+print ( result ) <EOL>
+a = 1 <EOL>
+result = a * 2 if a % 2 == 0 else a * 3 <EOL>
+print ( result ) <EOL>
+a = 2 <EOL>
+result = a * 2 if a % 2 == 0 else a * 3 <EOL>
+print ( result ) <EOL>
+a = 1 <EOL>
+print ( 'even' ) if a % 2 == 0 else print ( 'odd' ) <EOL>
+a = 1 <EOL>
+if a % 2 == 0 : <EOL>
+<INDENT>
+print ( 'even' ) <EOL>
+<OUTDENT>
+else : <EOL>
+<INDENT>
+print ( 'odd' ) <EOL>
+<OUTDENT>
+a = - 2 <EOL>
+result = 'negative and even' if a < 0 and a % 2 == 0 else 'positive or odd' <EOL>
+print ( result ) <EOL>
+a = - 1 <EOL>
+result = 'negative and even' if a < 0 and a % 2 == 0 else 'positive or odd' <EOL>
+print ( result ) <EOL>