Echo command syntax

Gamefanatic3D

I was working with the echo syntax to incorporate the ">" & ">>" capabilities and was using the persistentGlobal.g file identified in the "GCode Meta Commands. However, when executing the file I receive the error:

Error: in file macro line 6 column 7: meta command: expected a string expression

file: _TestVar1

M98 P"/sys/scripts/persistentGlobal.g" V"testVar" X"one"

After some back-and-forth, I found the root cause to be that the example had a space the ">" Removing the space resolved the problem. I only noticed this after looking at the earlier examples in the documentation which did not have the additional space where the filename was being provided.

Old code:

var id = param.V                    ; name of the global variable
var value = param.X                 ; value to save
var filepath = "globals/"^{var.id}  ; internal file path where the global variable is saved

; Save the global variable as a file so it is persistent
echo > {var.filepath} "if exists(global."^{var.id}^")"
echo >> {var.filepath} "    set global."^{var.id}^" = "^{var.value}
echo >> {var.filepath} "else"
echo >> {var.filepath} "    global "^{var.id}^" = "^{var.value}

M98 P{var.filepath} ; load the global variable

Working code:

var id = param.V                    ; name of the global variable
var value = param.X                 ; value to save
var filepath = "globals/"^{var.id}  ; internal file path where the global variable is saved

; Save the global variable as a file so it is persistent
echo >{var.filepath} "if exists(global."^{var.id}^")"
echo >>{var.filepath} "    set global."^{var.id}^" = "^{var.value}
echo >>{var.filepath} "else"
echo >>{var.filepath} "    global "^{var.id}^" = "^{var.value}

M98 P{var.filepath} ; load the global variable

I just thought I'd pass this along.

Using v3.6 rc1 & rc2 both produced the error.

gloomyandy

@Gamefanatic3D Are you running in standalone mode or using an SBC?

Gamefanatic3D

@gloomyandy Stand-alone mode.

dc42

@Gamefanatic3D that's correct, the syntax described at https://docs.duet3d.com/en/User_manual/Reference/Gcode_meta_commands#echo-command does not permit spaces after the > or >> or >>> symbol.

Gamefanatic3D

@dc42 Tracking the syntax. However with the example at the bottom of the page not following the syntax it's not clear, so I thought it worth reporting such that either the "Examples of Use" section or the syntax would be updated.

Saving and restoring variables across a reset

persistentGlobal.g
loadPersistentGlobal.g

dc42

@Gamefanatic3D thanks, I have corrected the persistentGlobal.g example.