node/try-catch: group err vars; simplify names; treat Exception as base case

node.go

@@ -654,7 +654,7 @@ func (this *conversionState) convertNoFreeFloating(n_ node.Node) (string, error)
 			handler = "// suppress error"
 		} else {
 
-			catchVars := ""
+			catchVars := []string{}
 			catchIfs := []string{}
 
 			for _, catch_ := range n.Catches {
@@ -676,25 +676,46 @@ func (this *conversionState) convertNoFreeFloating(n_ node.Node) (string, error)
 						return "", parseErr{catch_, err}
 					}
 
-					tempCatchVar := catchVar
-					if len(catch.Types) > 1 {
-						tempCatchVar += "_" + typename
+					if typename == `Exception` {
+						// PHP base type - catches all exceptions
+
+						catchStmt := catchBody
+						catchIfs = append(catchIfs, catchStmt)
+
+					} else {
+
+						tempCatchVar := catchVar
+						if len(catch.Types) > 1 {
+							tempCatchVar += "" + typename
+						}
+
+						// It's common for PHP types to have 'Exception' in the suffix
+						// We are probably free to elide that (stylistically)
+						if strings.HasSuffix(tempCatchVar, `Exception`) {
+							tempCatchVar = tempCatchVar[0 : len(tempCatchVar)-9]
+						}
+
+						catchVars = append(catchVars, tempCatchVar+"*"+typename)
+
+						catchStmt := "if errors.As(err, &" + tempCatchVar + ") {\n"
+						if len(catch.Types) > 1 {
+							catchStmt += catchVar + " := " + tempCatchVar + " // rename\n"
+						}
+						catchStmt += catchBody // contains its own {}
+						catchStmt += "}"       // but without trailing NL
+
+						catchIfs = append(catchIfs, catchStmt)
 					}
-
-					catchVars += "var " + tempCatchVar + "*" + typename + "\n"
-
-					catchStmt := "if errors.As(err, &" + tempCatchVar + ") {\n"
-					if len(catch.Types) > 1 {
-						catchStmt += catchVar + " := " + tempCatchVar + " // rename\n"
-					}
-					catchStmt += catchBody // contains its own {}
-					catchStmt += "} "      // but without trailing NL
-
-					catchIfs = append(catchIfs, catchStmt)
 				}
 			}
 
-			handler = catchVars + strings.Join(catchIfs, "else") + "\n"
+			handler = ""
+			if len(catchVars) == 1 {
+				handler += "var " + catchVars[0] + "\n"
+			} else {
+				handler += "var (\n" + strings.Join(catchVars, "\n") + "\n)\n"
+			}
+			handler += strings.Join(catchIfs, " else ") + "\n"
 		}
 
 		// Store the handler to be used going forwards