problem with function in prompt

problem with function in prompt

[Stephen Prater]

I have the following function in a sourced file..

function free_mem() {
   FM=$(ruby -e '
     x = `vm_stat`.each_line.to_a[0..4].join.scan(/([0-9]*?) 
\./).flatten.map { |i| (i.to_i * 4096) / 1000000 };
     y = `sysctl hw.memsize`.split(/:\s/).last.to_i / 1000000;
     puts "%F{82}#{x[0]}%f/%F{yellow}#{x[2]}%f/%F{69}#{y}%f";')
   echo $FM
}

and then in my prompt i have this:

$(free_mem)

The problem is that it never re-executes the function in the prompt ----

setopt prompt_subst

PROMPT_INFO="$(draw f21 ul hbar) $(host_name)- %L
$(draw f21 ll hbar) $(dir_name) $(free_mem)"
DEF_PROMPT="${(e)${PROMPT_INFO}} %F{cyan} [ %f"
INS_MODE_PROMPT="${(e)${PROMPT_INFO}} %F{red} [ %f"


The value that appears in the prompt is always the same as the one  
when the shell was initially executed.

I tried placing it in a variable within precmd and then using that  
variable in the prompt like this:

precmd() {
	FREE_MEM=$(free_mem)
}
PROMPT="$FREE_MEM"

but that didn't work either

If I call free_mem directly from the prompt (or echo FREE_MEM) it  
outputs the correct string... so what am I missing?

stephen

Re: problem with function in prompt

[René 'Necoro' Neumann]

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Am 24.03.2011 21:23, schrieb Stephen Prater:
> 
> The problem is that it never re-executes the function in the prompt ----
> 
> setopt prompt_subst
> 
> PROMPT_INFO="$(draw f21 ul hbar) $(host_name)- %L
> $(draw f21 ll hbar) $(dir_name) $(free_mem)"
> DEF_PROMPT="${(e)${PROMPT_INFO}} %F{cyan} [ %f"
> INS_MODE_PROMPT="${(e)${PROMPT_INFO}} %F{red} [ %f"
> 
> 
> The value that appears in the prompt is always the same as the one when
> the shell was initially executed.

You should use FOO='$bla' instead of FOO="$bla" -- with the latter, $bla
is evaluated while assigning -- with the first one, $bla is evaluated
while evaluating $FOO.

This means, with your current way, the variables and functions are all
computed while setting the prompt variable -- and then there is nothing
left to evaluate while printing the prompt :)

HTH,
- René


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