unexpected "|" in template clause

[estahn]

Template:

{{- template "base" -}}
{{ define "jobs" }}
  {{ template "job-checkout_code" | indent 4 }}
{{ end }}

Error message:
Error: template: -:39: unexpected "|" in template clause

[hairyhenderson]

Thanks for logging this, @estahn!

That doesn't seem to be quite the right syntax, though there's still a bug. Using the built-in js function, this fails in the same way:

$ gomplate -i '{{define "foo"}}hello world{{end}}{{ template "foo" | js }}'   
Error: template: <arg>:1: unexpected "|" in template clause

But this succeeds:

$ gomplate -i '{{define "foo"}}hello world{{end}}{{ template "foo" . | js }}'
hello world

This should succeed, but doesn't:

$ gomplate -i '{{define "foo"}}hello world{{end}}{{ template "foo" . | strings.ToUpper }}'
Error: template: <arg>:1:56: executing "<arg>" at <strings>: wrong type for value; expected string; got *main.Context

So, clearly there's something missing 😉

[hairyhenderson]

Ok, this is a pretty widely-scoped bug. Essentially, I have a number of functions that accept only strings, which should really be able to handle anything, converting to string as necessary.

Interestingly, at first glance strings.Indent isn't only accepting string, and indeed it gives a different error:

$ gomplate -i '{{define "foo"}}hello world{{end}}{{ template "foo" . | strings.Indent }}' 
2018/04/18 20:39:19 Indent: invalid arguments

This is because it takes ...interface{} as its arguments. It immediately fails if the last element in that array is a non-string, though.

All this to say - the fix for strings.Indent/indent will be slightly different than the fix for every other function that expects a string.

I'm on it - just need to step out for a quick jog and I'll try and get a fix drafted tonight or tomorrow 👍

[hairyhenderson]

Ok, further discovery - my reading of the template docs was way off... When rendering templates of the form {{ template "T1" pipeline }}, I thought the T1 template would be piped through pipeline, but that's not at all true - instead the value set by pipeline is passed to T1 as the context (.):

$ gomplate -i '{{ define "T1" }}hello {{ . }}{{end}}{{template "T1" "world" | strings.ToUpper }}'
hello WORLD
$ gomplate -i '{{ define "T1" }}hello {{ .hello }}{{end}}{{template "T1" data.JSON `{"hello":"world"}` }}'
hello world

So, based on all this, this isn't a bug in gomplate, but a simple syntax issue.

I'd be nice to be able to handle many different kinds of input to the functions in the strings namespace, but that's orthogonal to this issue.

I'm going to close this now - feel free to re-open if you disagree 🙂

[estahn]

I feel that helps sort of with #291 , but don't see how it will help with the indentation of the output of {{ template ...}}.

[hairyhenderson]

don't see how it will help with the indentation of the output of {{ template ...}}.

I'm not sure this is possible with template unfortunately. You'd have to alter it where it's defined, which may or may not be awkward:

$ gomplate -i '{{ define "T1" }}{{ strings.Indent .width "." "hello world" }}{{ end -}}
{{ template "T1" data.YAML "width: 3" }}
{{ template "T1" data.YAML "width: 4" }}'
...hello world
....hello world

Hope that helps!

[estahn]

@hairyhenderson Thanks for the support and quick turnaround. 👍

[hairyhenderson]

🙇

[RevantBabu]

The other approach I think (especially while including template files) is to use tmpl.Exec (that returns a string which can be piped to strings.Indent)

{{ tmpl.Exec "t/input.tmpl" . | strings.Indent 4 }}