Added --noCppExceptions switch

compiler/ccgexprs.nim

@@ -2111,8 +2111,10 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
       initLocExpr(p, n.sons[0], a)
   of nkAsmStmt: genAsmStmt(p, n)
   of nkTryStmt:
-    if p.module.compileToCpp: genTryCpp(p, n, d)
+    if p.module.compileToCpp and optNoCppExceptions notin gGlobalOptions:
-    else: genTry(p, n, d)
+      genTryCpp(p, n, d)
+    else:
+      genTry(p, n, d)
   of nkRaiseStmt: genRaiseStmt(p, n)
   of nkTypeSection:
     # we have to emit the type information for object types here to support

compiler/commands.nim

@@ -619,6 +619,10 @@ proc processSwitch(switch, arg: string, pass: TCmdLinePass, info: TLineInfo) =
     cAssembler = nameToCC(arg)
     if cAssembler notin cValidAssemblers:
       localError(info, errGenerated, "'$1' is not a valid assembler." % [arg])
+  of "nocppexceptions":
+    expectNoArg(switch, arg, pass, info)
+    incl(gGlobalOptions, optNoCppExceptions)
+    defineSymbol("noCppExceptions")
   else:
     if strutils.find(switch, '.') >= 0: options.setConfigVar(switch, arg)
     else: invalidCmdLineOption(pass, switch, info)

compiler/options.nim

@@ -66,6 +66,7 @@ type                          # please make sure we have under 32 options
                               # also: generate header file
     optIdeDebug               # idetools: debug mode
     optIdeTerse               # idetools: use terse descriptions
+    optNoCppExceptions        # use C exception handling even with CPP
   TGlobalOptions* = set[TGlobalOption]
   TCommands* = enum           # Nim's commands
                               # **keep binary compatible**

doc/advopt.txt

@@ -69,6 +69,7 @@ Advanced options:
   --putenv:key=value        set an environment variable
   --NimblePath:PATH         add a path for Nimble support
   --noNimblePath            deactivate the Nimble path
+  --noCppExceptions         use default exception handling with C++ backend
   --excludePath:PATH        exclude a path from the list of search paths
   --dynlibOverride:SYMBOL   marks SYMBOL so that dynlib:SYMBOL
                             has no effect and can be statically linked instead;

lib/system/excpt.nim

@@ -216,7 +216,7 @@ proc raiseExceptionAux(e: ref Exception) =
     if not localRaiseHook(e): return
   if globalRaiseHook != nil:
     if not globalRaiseHook(e): return
-  when defined(cpp):
+  when defined(cpp) and not defined(noCppExceptions):
     if e[] of OutOfMemError:
       showErrorMessage(e.name)
       quitOrDebug()

web/news.txt

@@ -17,6 +17,13 @@ Library Additions
 - The rlocks module has been added providing reentrant lock synchronization
   primitive
 
+Compiler Additions
+------------------
+
+- Added a new ``--noCppExceptions`` switch that allows to use default exception
+  handling (no ``throw`` or ``try``/``catch`` generated) when compiling to C++
+  code
+
 
 2016-01-27 Nim in Action is now available!
 ==========================================