Added alternate syntax for conditionals in "then" clauses.

New syntax: if ... then { ... } else ...

AST.ml

@@ -406,12 +406,16 @@ and conditional = {
   kwd_if     : kwd_if;
   test       : test_expr;
   kwd_then   : kwd_then;
-  ifso       : instruction;
+  ifso       : ifso;
   terminator : semi option;
   kwd_else   : kwd_else;
   ifnot      : instruction
 }
 
+and ifso =
+  ThenInstr of instruction
+| ThenBlock of (instructions * semi option) braces reg
+
 and test_expr =
   GenExpr of expr
 | SetMem  of set_membership reg
@@ -1072,11 +1076,21 @@ and print_conditional node =
   print_token       kwd_if "if";
   print_test_expr   test;
   print_token       kwd_then "then";
-  print_instruction ifso;
+  print_ifso        ifso;
   print_terminator  terminator;
   print_token       kwd_else "else";
   print_instruction ifnot
 
+and print_ifso = function
+  ThenInstr instr -> print_instruction instr
+| ThenBlock {value; _} ->
+    let {lbrace; inside; rbrace} = value in
+    let instr, terminator = inside in
+    print_token lbrace "{";
+    print_instructions instr;
+    print_terminator   terminator;
+    print_token rbrace "}"
+
 and print_test_expr = function
   GenExpr e -> print_expr e
 | SetMem  m -> print_set_membership m

AST.mli

@@ -390,12 +390,16 @@ and conditional = {
   kwd_if     : kwd_if;
   test       : test_expr;
   kwd_then   : kwd_then;
-  ifso       : instruction;
+  ifso       : ifso;
   terminator : semi option;
   kwd_else   : kwd_else;
   ifnot      : instruction
 }
 
+and ifso =
+  ThenInstr of instruction
+| ThenBlock of (instructions * semi option) braces reg
+
 and test_expr =
   GenExpr of expr
 | SetMem  of set_membership reg

Parser.mly

@@ -580,7 +580,7 @@ proc_call:
   fun_call { $1 }
 
 conditional:
-  If test_expr Then instruction option(SEMI) Else instruction {
+  If test_expr Then ifso option(SEMI) Else instruction {
     let region = cover $1 (instr_to_region $7) in
     let value = {
       kwd_if     = $1;
@@ -593,6 +593,20 @@ conditional:
     in {region; value}
   }
 
+ifso:
+  instruction {
+    ThenInstr $1
+  }
+| LBRACE series(instruction,RBRACE) {
+   let first, (others, terminator, closing) = $2 in
+   let region = cover $1 closing in
+   let value = {
+     lbrace = $1;
+     inside = (first, others), terminator;
+     rbrace = closing} in
+   ThenBlock {value; region}
+  }
+
 test_expr:
   expr           { GenExpr $1 }
 | set_membership {  SetMem $1 }

Tests/crowdfunding.ligo

@@ -28,12 +28,11 @@ entrypoint withdraw (storage store : store; const sender : address)
   begin
     if sender = owner then
       if now (Unit) >= store.deadline then
-        if balance >= store.goal then
-          begin
+        if balance >= store.goal then {
              store.funded := True;
 //           patch store with record funded = True end;
-             operations := [Transfer (owner, balance)]
-          end
+             operations := [Transfer (owner, balance)];
+        };
         else fail "Below target"
       else fail "Too soon"
     else skip