| Title: | A System for Working with Templates |
| Version: | 0.4.0 |
| Description: | Provides tools to work with template code and text in R. It aims to provide a simple substitution mechanism for R-expressions inside these templates. Templates can be written in other languages like 'SQL', can simply be represented by characters in R, or can themselves be R-expressions or functions. |
| Depends: | R (≥ 3.4.0) |
| Imports: | stringr, magrittr |
| License: | MIT + file LICENSE |
| Encoding: | UTF-8 |
| Suggests: | testthat, knitr, rmarkdown, covr |
| RoxygenNote: | 6.1.1 |
| VignetteBuilder: | knitr |
| NeedsCompilation: | no |
| Packaged: | 2024-03-15 11:35:25 UTC; lswarnholz |
| Author: | Sebastian Warnholz [aut, cre] |
| Maintainer: | Sebastian Warnholz <wahani@gmail.com> |
| Repository: | CRAN |
| Date/Publication: | 2024-03-15 11:50:02 UTC |
Template constructors
Description
tmpl is the constructor function for template objects.
Usage
tmpl(.t, ...)
## S3 method for class 'character'
tmpl(.t, ..., .envir = parent.frame())
## S3 method for class 'formula'
tmpl(.t, ...)
## S3 method for class 'tmpl'
tmpl(.t, ...)
## S3 method for class 'function'
tmpl(.t, ...)
Arguments
.t |
something that can be interpreted as template. See defined methods for options. |
... |
(name = value | name ~ value) name-value expressions passed on to tmplUpdate |
.envir |
(environment) the environment in which template snippets are
evaluated. For |
Details
Objects of class tmpl are stored as a character of length
one. They can contain 'snippets' to be evaluated. These snippets are
identified by an opening {{ and closing }}. The
environment in which they are evaluated is stored in the object. They can
be further augmented by supplying arguments in ....
See Also
Examples
tmpl("Hi {{ toupper(a) }}!", a = "there")
tmpl( ~ {y <- {{ a }}}, a ~ x + 1)
tmpl(function(x) {{ a }} + x, a ~ 1)
Update and evaluate templates
Description
Functions operating on tmpl objects. They can be updated and / or evaluated as an expression.
Usage
tmplUpdate(.t, ...)
## S3 method for class 'tmpl'
tmplUpdate(.t, ...)
## S3 method for class 'function'
tmplUpdate(.t, ...)
tmplEval(.t, ..., .envir = new.env(parent = parent.frame()))
tmplAsFun(.t, ...)
Arguments
.t |
(tmpl) and object of class |
... |
(name = value | name ~ value) name-value expressions used to
update the snippets in |
.envir |
(environment) the environment in which the template is evaluated |
Details
tmplUpdate will evaluate all snippets in a template. Objects are
searched for in the list of arguments supplied as ... and the
environment of the template. The results are substituted within the snippets.
tmplEval will evaluate the template in place or in the specified
environment after substituting the elements in ....
Examples
tmpl("This is {{ a }} very similar to {{ b }}", a = "actually", b = "sprintf")
tmpl("But I consider it to be ({{ sprintf('%i', a) }}) orthogonal", a = 1.0)
tmpl("and ({{ sprintf('%i', b) }}) with a different scope:", b = 2.0)
tmpl("SELECT {{ var }} FROM {{ table }} WHERE {{ condition }};",
var = "someVar", table = "someTable", condition = "primaryKey = 1")
template <- tmpl("cat({{ toupper(x) }})")
tmplUpdate(template, x ~ "hi")
tmplEval(template, x ~ "hi")