xelim: supports try statements now (#22)

src/xelim/xelim_model.nim

@@ -42,6 +42,9 @@ type
     WhileX = "while"
     CaseX = "case"
     OfX = "of"
+    TryX = "try"
+    ExceptX = "except"
+    FinallyX = "fin"
     ProcX = "proc"
 
     StmtsX = "stmts"

src/xelim/xelim_transformer.nim

@@ -180,6 +180,40 @@ proc trCase(c: var Context; dest: var Tree; t: Tree; n: NodePos; tar: var Target
   if tar.m != IsIgnored:
     tar.t.addAtom Sym, tmp, info
 
+proc trTry(c: var Context; dest: var Tree; t: Tree; n: NodePos; tar: var Target) =
+  let info = t[n].info
+  var tmp = StrId(0)
+
+  if tar.m != IsIgnored:
+    tmp = declareTemp(c, dest, info, AutoX)
+
+  copyIntoFrom(dest, t, n):
+    if tar.m != IsIgnored:
+      trExprInto c, dest, t, n.firstSon, tmp
+
+    for ch in sonsFromX(t, n):
+      case t[ch].kind
+      of ExceptX:
+        copyIntoFrom(dest, t, ch):
+          for e in sons(t, ch):
+            if isLastSon(t, ch, e):
+              if tar.m != IsIgnored:
+                trExprInto c, dest, t, e, tmp
+              else:
+                trStmt c, dest, t, e
+            else:
+              copyTree dest, t, e
+      of FinallyX:
+        # The `finally` section never produces a value!
+        copyIntoFrom(dest, t, ch):
+          let action = ch.firstSon
+          trStmt c, dest, t, action
+      else:
+        # Bug: just copy the thing around
+        copyTree dest, t, n
+  if tar.m != IsIgnored:
+    tar.t.addAtom Sym, tmp, info
+
 proc trStmt(c: var Context; dest: var Tree; t: Tree; n: NodePos) =
   case t[n].kind
   of Empty, Tag:
@@ -193,6 +227,9 @@ proc trStmt(c: var Context; dest: var Tree; t: Tree; n: NodePos) =
   of CaseX:
     var tar = Target(m: IsIgnored)
     trCase c, dest, t, n, tar
+  of TryX:
+    var tar = Target(m: IsIgnored)
+    trTry c, dest, t, n, tar
 
   of RetX, DiscardX, RaiseX, YieldX:
     var tar = Target(m: IsEmpty)
@@ -259,6 +296,8 @@ proc trExpr(c: var Context; dest: var Tree; t: Tree; n: NodePos; tar: var Target
     trIf c, dest, t, n, tar
   of CaseX:
     trCase c, dest, t, n, tar
+  of TryX:
+    trTry c, dest, t, n, tar
   of AndX:
     trAnd c, dest, t, n, tar
   of OrX:

tests/xelim/t2.expected.nif

@@ -42,4 +42,15 @@
      (lt 4 5)
      (call echo "body"))
     (else
-     (break))))))
+     (break)))))
+ (var :tmp.3.01 . .
+  (auto) .)
+ (try
+  (call echo "abc")
+  (asgn tmp.3.01 3)
+  (except
+   (as :e E.t)
+   (asgn tmp.3.01 90))
+  (fin
+   (call echo "90")))
+ (var :x.3 . . . tmp.3.01))

tests/xelim/t2.nif

@@ -4,4 +4,5 @@
     (if (elif cond "action") (else "abc"))
   )))
   (while (expr (call echo "hi\00") (lt 4 5)) (call echo "body"))
+  (var :x.3 ... (try (expr (call echo "abc") 3) (except (as :e E.t) 90) (fin (call echo "90")) ))
 )