.\" Copyright (c) 2022 Omar Polo .\" .\" 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 06, 2022 .Dt TEMPLATE 7 .Os .Sh NAME .Nm template .Nd templating language .Sh DESCRIPTION .Nm is a language used to define programs that output data in some way. These programs are called .Dq templates . A .Nm file is assumed to be compiled using the .Xr template 1 utility into C code, to be further compiled as part of a bigger application. The language itself is format-agnostic and can thus be used to produce various type of outputs. .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 C 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 C function that output its content via some provided functions. Here's an example of a block: .Bd -literal -offset indent {{ define tp_base(struct template *tp, const char *title) }} {{ title }} {{ render tp->tp_body(tp) }} {{ 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 -1. 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 C for loop. .It Cm {{ Ic tailq-foreach Ar var head fieldname Cm }} Ar .. Cm {{ Ic end Cm }} Looping construct similar to the queue.h macro TAILQ_FOREACH. .It Cm {{ Ic while Ar ... Cm }} Ar ... Cm {{ Ic end Cm }} Looping construct similar to the C while loop. .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 escaping. .El .Sh SEE ALSO .Xr template 1 .Sh AUTHORS .An -nosplit The .Nm reference was written by .An Omar Polo Aq Mt op@openbsd.org .