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

Description

Take a template job (i.e., a list of template rules), or a template rule, and create a job (or rule) from them by replacing rmake variables in the template with their values. The rmake variable is a identified by the $[VARIABLE_NAME] string anywhere in the definition of a rule.

Usage

expandTemplate(template, vars)

Arguments

template

An instance of the S3 rmake.rule class or a list of such objects.

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.

Value

A list of rules created from template by replacing rmake variables.

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.

Examples

Run this code

# NOT RUN {
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'))
# }