Warning: Due to various recent migrations, viewing non-HEAD refs may be broken.
/htmplgen/htmpl.7 (raw)
.\" Copyright (c) 2022 Omar Polo <op@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd January 6, 2022
.Dt TEMPLATE 7
.Os
.Sh NAME
.Nm htmpl
.Nd templating language
.Sh DESCRIPTION
.Nm
is a language used to define programs that output HTML.
These programs are called
.Dq templates .
A
.Nm
file is assumed to be compiled using the
.Xr htmplgen 1
utility into Hare code, to be further compiled as part of a bigger
application.
.Pp
There are two special sequences:
.Bl -tag -width 9m
.It Cm {{ Ar ... Cm }}
used for
.Nm
special syntax.
.It Cm {! Ar ... Cm !}
used to include literal Hare code.
This is the only special syntax permitted as top-level, except for block
definition and includes.
.El
.Pp
The basic unit of a
.Nm
file is the block.
Each block is turned into a Hare function that output its content via some
provided functions. The block must accept an argument called
.Ar handle
that satisfies io::handle.
.Pp
Here's an example of a block:
.Bd -literal -offset indent
{{ define tp_base(handle: io::handle, title: str) (void | io::error | nomem) }}
<!doctype html>
<html>
<head>
<title>{{ title }}</title>
</head>
<body>
{{ render tp_body(tp) }}
</body>
</html>
{{ end }}
.Ed
.Ss SPECIAL SYNTAX
This section is a reference for all the special syntaxes supported.
.Bl -tag -width Ds
.It Cm {{ Ic include Ar file Cm }}
Include additional template files.
.It Cm {{ Ic define Ar name Ns ( Ar arguments ... ) Cm }} Ar body Cm {{ Ic end Cm }}
Defines the block
.Ar name
with the given
.Ar arguments .
.Ar body
will be outputted as-is via the provided functions
.Pq i.e.\& is still escaped eventually
and can contain all the special syntaxes documented here except
.Ic include
and
.Ic define .
.It Cm {{ Ic render Ar expression() Cm }}
Executes
.Ar expression()
and terminate the template if it returns an error.
It's used to render (call) another template.
.It Cm {{ Ic printf Ar fmt , Ar arguments ... Cm }}
Outputs the string that would be produced by calling
.Xr printf 3
with the given
.Ar fmt
format string and the given
.Ar arguments .
.It Cm {{ Ic if Ar expr Cm }} Ar ... Cm {{ Ic elseif Ar expr Cm }} Ar ... Cm {{ Ic else Cm }} Ar ... Cm {{ Ic end Cm }}
Conditional evaluation.
.Ic elseif
can be provided zero or more times,
.Ic else
only zero or one time and always for last.
.It Cm {{ Ic for Ar ... ; Ar ... ; Ar ... Cm }} Ar ... Cm {{ Ic end Cm }}
Looping construct similar to the Hare for loop.
.It Cm {{ Ic while Ar ... Cm }} Ar ... Cm {{ Ic end Cm }}
Looping construct similar to the Hare for loop with one condition argument only.
.It Cm {{ Ar expression Cm \&| Ic unsafe Cm }}
Output
.Ar expression
as-is.
.It Cm {{ Ar expression Cm \&| Ic urlescape Cm }}
Output
.Ar expression
escaped in a way that can be made part of an URL.
.It Cm {{ Ar expression Cm }}
Output
.Ar expression
with the default HTML escaping.
.El
.Sh SEE ALSO
.Xr htmplgen 1
.Sh AUTHORS
.An Omar Polo Aq Mt op@openbsd.org
wrote the original program.
.An Runxi Yu Aq Mt op@openbsd.org
ported it to Hare.