Can't use % as escape character in a template

[dargueta]

Suppose we have the following code:

tpl = [[
% for k, v in pairs(values) do
$(k) = $(v)
% end
]]

text = template.substitute(
    tpl,
    {
         _escape = '%',
         _parent = _G,
        values = {a = 1, b = 2, c = 3}
    }
)
print(text)

It appears the escape has no effect:

% for k, v in pairs(tbl) do
 = 
% end

If we use something else, like !, we get the expected result:

c = 3
a = 1
b = 2

I think we can fix this by passing plain=true to the strfind() calls here, e.g.

-- Instead of this:
local _, e, lua = strfind(chunk,esc_pat1, s)

-- Do this:
local _, e, lua = strfind(chunk,esc_pat1, s, 1, true)

Environment:
OS: Ubuntu 22.04
Lua: 5.4.4
Penlight: 1.13.1

[alerque]

Can you send a PR for this? I think you fix looks like it will be correct, but we'll want to see some test results, which a PR should show us.

[dargueta]

Done: #452

After a bit of tinkering I realized I needed to use string escaping rather than a literal search so that the inline escape would work as well.

[dargueta]

Fixed by #452