expandTemplate: Expand template rules into a list of rules by replacing...

In rmake: Makefile Generator for R Analytical Projects

Expand template rules into a list of rules by replacing rmake variables with their values

Description

The functionality of expandTemplate() differs accordingly to the type of the first argument. If the first argument is a template job (i.e., a list of template rules), or a template rule, then a job is created from templates by replacing rmake variables in templates with values of these variables, as specified in the second argument. The rmake variable is a part of a string in the format of ⁠$[VARIABLE_NAME]⁠.

Usage

expandTemplate(template, vars)

Arguments

template	An instance of the S3 rmake.rule class, or a list of such objects, or a character vector.
vars	A named character vector, matrix, or data frame with variable definitions. For character vector, names are variable names, values are variable values. For matrix or data frame, colnames are variable names and column values are variable values.

Details

If vars is a character vector then all variables in vars are replaced in template so that the result will contain length(template) rules. If vars is a data frame or a character matrix then the replacement of variables is performed row-wisely. That is, a new sequence of rules is created from template for each row of variables in vars so that the result will contain nrow(vars) * length(template) rules.

If the first argument of expandTemplate() is a character vector then the result is a character vector created by row-wise replacements of rmake variables, similarly as in the case of template jobs. See examples.

Value

If template is an instance of the S3 rmake.rule class, or a list of such objects, a list of rules created from template by replacing rmake variables is returned. If template is a character vector then a character vector with all variants of rmake values is returned.

Author(s)

Michal Burda

See Also

replaceVariables(), rule()

Examples

# Examples with template jobs and rules:

tmpl <- rRule('data-$[VERSION].csv', 'process-$[TYPE].R', 'output-$[VERSION]-$[TYPE].csv')

job <- expandTemplate(tmpl, c(VERSION='small', TYPE='a'))
# is equivalent to
job <- list(rRule('data-small.csv', 'process-a.R', 'output-small-a.csv'))

job <- expandTemplate(tmpl, expand.grid(VERSION=c('small', 'big'), TYPE=c('a', 'b', 'c')))
# is equivalent to
job <- list(rRule('data-small.csv', 'process-a.R', 'output-small-a.csv'),
            rRule('data-big.csv', 'process-a.R', 'output-big-a.csv'),
            rRule('data-small.csv', 'process-b.R', 'output-small-b.csv'),
            rRule('data-big.csv', 'process-b.R', 'output-big-b.csv'),
            rRule('data-small.csv', 'process-c.R', 'output-small-c.csv'),
            rRule('data-big.csv', 'process-c.R', 'output-big-c.csv'))


# Examples with template character vectors:
expandTemplate('data-$[MAJOR].$[MINOR].csv',
               c(MAJOR=3, MINOR=1))
# returns: c('data-3.1.csv')

expandTemplate('data-$[MAJOR].$[MINOR].csv',
               expand.grid(MAJOR=c(3:4), MINOR=c(0:2)))
# returns: c('data-3.0.csv', 'data-4.0.csv',
#            'data-3.1.csv', 'data-4.1.csv',
#            'data-3.2.csv', 'data-4.2.csv')

rmake documentation built on Aug. 26, 2025, 5:09 p.m.