fix: clj_ prefix for identifiers + try/catch/finally fixes

- #9: Add clj_ prefix to all mangled identifiers to avoid Nim
  case-insensitive name conflicts (parseQueryString ≡ parse_query_string)
- #11: Fix finally block - discard expression results
- #11: Fix catch handler - use original name for scope tracking
- Fix loop handler - use original name for addToScope
- Update emitter tests for clj_ prefix

src/emitter.nim

@@ -79,6 +79,8 @@ proc mangleName*(name: string): string =
                      "interface", "lambda", "open", "quit", "result", "nil", "end"]
   if result in nimKeywords:
     result = result & "1"
+  # Prefix to avoid conflicts with Nim identifiers (case-insensitive + underscore ignoring)
+  result = "clj_" & result
 
 proc pushScope() =
   scopeStack.add(initHashSet[string]())
@@ -1165,7 +1167,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
       raise newException(EmitterError, "loop bindings must be a vector")
     if bindings.items.len mod 2 != 0:
       raise newException(EmitterError, "loop bindings must have even number of elements")
-    var loopParams: seq[(string, string)] = @[]
+    var loopParams: seq[(string, string, string)] = @[]  # (mangled, original, value)
     var li = 0
     while li < bindings.items.len:
       var lname = bindings.items[li]
@@ -1175,13 +1177,13 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
         lname = lname.items[1]
       if lname.kind != ckSymbol:
         raise newException(EmitterError, "loop binding name must be a symbol")
-      loopParams.add((mangleName(lname.symName), emitExpr(lval, 0)))
+      loopParams.add((mangleName(lname.symName), lname.symName, emitExpr(lval, 0)))
       li += 2
     var loopVars: seq[string] = @[]
     var lines: seq[string] = @[]
     pushScope()
-    for (lpName, lpVal) in loopParams:
-      addToScope(lpName)
+    for (lpName, lpOrig, lpVal) in loopParams:
+      addToScope(lpOrig)
       lines.add(sp & "var " & lpName & ": CljVal = " & lpVal)
       loopVars.add(lpName)
     loopStack.add(loopVars)
@@ -1271,7 +1273,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
     if items.len < 2:
       raise newException(EmitterError, "try requires body")
     var bodyForms: seq[CljVal] = @[]
-    var catchClauses: seq[(string, string, seq[CljVal])] = @[]
+    var catchClauses: seq[(string, string, string, seq[CljVal])] = @[]  # (exType, mangledName, origName, body)
     var finallyBody: seq[CljVal] = @[]
     var ti = 1
     while ti < items.len:
@@ -1304,7 +1306,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
           let exName = form.items[nameIdx]
           if exName.kind != ckSymbol:
             raise newException(EmitterError, "catch name must be a symbol")
-          catchClauses.add((exTypeStr, mangleName(exName.symName), form.items[bodyIdx..^1]))
+          catchClauses.add((exTypeStr, mangleName(exName.symName), exName.symName, form.items[bodyIdx..^1]))
         elif form.items[0].symName == "finally":
           finallyBody = form.items[1..^1]
         else:
@@ -1330,7 +1332,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
           lines.add(code)
         else:
           lines.add(indentStr(indent + 1) & "discard " & stripped)
-    for (exType, exVar, exBody) in catchClauses:
+    for (exType, exVar, exOrig, exBody) in catchClauses:
       lines.add(sp & "except " & exType & ":")
       lines.add(indentStr(indent + 1) & "let " & exVar & " = cljMap(@[cljKeyword(\"message\")], @[cljString(getCurrentExceptionMsg())])")
       lines.add(indentStr(indent + 1) & "discard cljAssoc(" & exVar & ", cljKeyword(\"type\"), cljString(\"" & exType & "\"))")
@@ -1338,7 +1340,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
       lines.add(indentStr(indent + 1) & "if exPtr" & exVar & " of ExInfo:")
       lines.add(indentStr(indent + 2) & "discard cljAssoc(" & exVar & ", cljKeyword(\"data\"), (ref ExInfo)(exPtr" & exVar & ").exData)")
       pushScope()
-      addToScope(exVar)
+      addToScope(exOrig)
       for i, eb in exBody:
         let isLast = (i == exBody.len - 1)
         let code = emitExpr(eb, indent + 1)
@@ -1359,7 +1361,15 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
     if finallyBody.len > 0:
       lines.add(sp & "finally:")
       for fb in finallyBody:
-        lines.add(emitExpr(fb, indent + 1))
+        let fbCode = emitExpr(fb, indent + 1)
+        let fbStripped = fbCode.strip()
+        if fbStripped.startsWith("echo ") or fbStripped.startsWith("discard ") or
+           fbStripped.startsWith("var ") or fbStripped.startsWith("let ") or
+           fbStripped.startsWith("proc ") or fbStripped.startsWith("if ") or
+           fbStripped.startsWith("try:") or fbStripped.startsWith("while "):
+          lines.add(fbCode)
+        else:
+          lines.add(indentStr(indent + 1) & "discard " & fbStripped)
     return lines.join("\n")
 
   of "throw":