knitr (version 1.10.5)

knit_expand: A simple macro preprocessor for templating purposes

Description

This function expands a template based on the R expressions in {{}} (this tag can be customized by the delim argument). These expressions are extracted, evaluated and replaced by their values in the original template.

Usage

knit_expand(file, ..., text = readLines(file, warn = FALSE), delim = c("{{", "}}"))

Arguments

file

the template file

...

a list of variables to be used for the code in the template; note the variables will be searched in the parent frame as well

text

an alternative way to file to specify the template code directly (if provided, file will be ignored)

delim

the (opening and ending) delimiters for the templating tags

Value

• A character vector, with the tags evaluated and replaced by their values.

References

This function was inspired by the pyexpander (http://pyexpander.sourceforge.net) and m4 (http://www.gnu.org/software/m4/), thanks to Frank Harrell.

Examples

# see the knit_expand vignette
if (interactive()) browseVignettes(package = "knitr")