diff --git a/node.go b/node.go
index 9b84ada..e5163ea 100644
--- a/node.go
+++ b/node.go
@@ -1208,6 +1208,69 @@ func (this *conversionState) convertNoFreeFloating(n_ node.Node) (string, error)
 		} else if funcName == `extract` {
 			return "", parseErr{n, fmt.Errorf("Unsupported dynamic function `\\extract()`")}
 
+		} else if funcName == `var_dump` {
+			// This is mostly called for debugging purposes. Printf should be good enough
+			this.importPackages["fmt"] = struct{}{}
+			callParams = append([]string{`"%#v\n"`}, callParams...) // Insert extra 1st parameter
+			funcName = `fmt.Printf`
+
+		} else if funcName == `max` {
+			this.importPackages["math"] = struct{}{}
+			funcName = `math.Max` // n.b. only works on 2 integers, not as wide as PHP's version
+
+		} else if funcName == `min` {
+			this.importPackages["math"] = struct{}{}
+			funcName = `math.Max` // n.b. only works on 2 integers, not as wide as PHP's version
+
+		} else if funcName == `floor` {
+			this.importPackages["math"] = struct{}{}
+			funcName = `math.Floor`
+
+		} else if funcName == `var_export` || funcName == `print_r` {
+
+			if len(callParams) == 1 {
+				this.importPackages["fmt"] = struct{}{}
+				callParams = append([]string{`"%#v\n"`}, callParams...) // Insert extra 1st parameter
+				funcName = `fmt.Printf`
+
+			} else if len(callParams) == 2 {
+				// Returning form
+				this.importPackages["fmt"] = struct{}{}
+				callParams = append([]string{`"%#v\n"`}, callParams...) // Insert extra 1st parameter
+				funcName = `fmt.Sprintf`
+
+			} else {
+				return "", parseErr{n, fmt.Errorf("Call to '%s' expected 3 or 4 argument(s), got %d", funcName, len(callParams))}
+
+			}
+
+		} else if funcName == `substr` {
+			// substr($string, $start [, $length]) => new string
+			// In Go all strings are immutable, and slicing an existing string produces a new immutable string so that works out
+
+			if len(callParams) == 2 {
+				return "(" + callParams[0] + ")[" + callParams[1] + ":]", nil
+
+			} else if len(callParams) == 3 {
+				// if lnum, ok := n.ArgumentList.Arguments[1].
+
+				// WARNING: We are doubling up on the first parameter
+				// This is a problem if it's not necessarily constant
+
+				return "(" + callParams[0] + ")[" + callParams[1] + ":" + callParams[1] + `+` + callParams[2] + "]", nil
+
+			} else {
+				return "", parseErr{n, fmt.Errorf("Call to '%s' expected 2 or 3 argument(s), got %d", funcName, len(callParams))}
+			}
+
+		} else if funcName == `rename` {
+			if len(callParams) != 2 {
+				return "", parseErr{n, fmt.Errorf("Call to '%s' expected 2 argument(s), got %d", funcName, len(callParams))}
+			}
+
+			this.importPackages["os"] = struct{}{}
+			funcName = `os.Rename`
+
 		}
 
 		return funcName + "(" + strings.Join(callParams, ", ") + ")", nil // expr only, no semicolon/newline