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stand-alone except and finally blocks

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This is equivalent to the on-error and at-scope-exit operators in other languages
This commit is contained in:
Zahary Karadjov 2012-05-23 02:25:16 +03:00
commit b1574bb0e0
4 changed files with 69 additions and 30 deletions
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34
compiler/semstmts.nim
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@ -871,13 +871,33 @@ proc SemStmt(c: PContext, n: PNode): PNode =
of nkBlockStmt: result = semBlock(c, n)
of nkStmtList:
var length = sonsLen(n)
for i in countup(0, length - 1):
n.sons[i] = semStmt(c, n.sons[i])
if n.sons[i].kind in LastBlockStmts:
for j in countup(i + 1, length - 1):
case n.sons[j].kind
of nkPragma, nkCommentStmt, nkNilLit, nkEmpty: nil
else: localError(n.sons[j].info, errStmtInvalidAfterReturn)
for i in countup(0, length - 1):
case n.sons[i].kind
of nkFinally, nkExceptBranch:
# stand-alone finally and except blocks are
# transformed into regular try blocks:
#
# var f = fopen("somefile") | var f = fopen("somefile")
# finally: fcsole(f) | try:
# ... | ...
# | finally:
# | fclose(f)
var tryStmt = newNodeI(nkTryStmt, n.sons[i].info)
var body = newNodeI(nkStmtList, n.sons[i].info)
if i < n.sonsLen - 1:
body.sons = n.sons[(i+1)..(-1)]
tryStmt.addSon(body)
tryStmt.addSon(n.sons[i])
n.sons[i] = semTry(c, tryStmt)
n.sons.setLen(i+1)
return
else:
n.sons[i] = semStmt(c, n.sons[i])
if n.sons[i].kind in LastBlockStmts:
for j in countup(i + 1, length - 1):
case n.sons[j].kind
of nkPragma, nkCommentStmt, nkNilLit, nkEmpty: nil
else: localError(n.sons[j].info, errStmtInvalidAfterReturn)
of nkRaiseStmt: result = semRaise(c, n)
of nkVarSection: result = semVarOrLet(c, n, skVar)
of nkLetSection: result = semVarOrLet(c, n, skLet)