How to use madx.help()

[Landau1908]

Hi, Thomas
I want to obtain the help information about a madx command via madx.help(), but I can't obtain anything. How to do?

from cpymad.madx import Madx
madx = Madx()
print madx.help("twiss")

output:

None

[coldfix]

the output of the help command is just printed to STDOUT - so unless you close STDOUT, you don't need print. There is also a way to get the text in a variable by temporarily capturing STDOUT (in the remote process), but you will have to code that on your own.

[Eothred]

Looking at https://github.com/hibtc/cpymad/blob/master/cpymad/madx.py#L303, I think there is a minor error (relates to this question).

The line is self.command.help(cmd=cmd) which I think means that madx.help('twiss') is sent to madx as help,cmd='twiss';. Perhaps it should be self.command.help(cmd), which would result in madx getting the call `help,twiss;' instead.

[coldfix]

you're right, the quotes don't work. I had changed the generic representation of string values from bare words to quoted strings in c35c533 due to another issue. I will add a fix later.