rule: General creator of an instance of the S3 `rmake.rule` class

Description

Rule is an atomic element of the build process. It defines a set of target file names, which are to be built with a given build command from a given set depends of files that targets depend on, and which can be removed by a given clean command.

Usage

rule(target, depends = NULL, build = NULL, clean = NULL,
  task = "all", phony = FALSE, type = "")

Arguments

target

A character vector of target file names that are created by the given build command

depends

A character vector of file names the build command depends on

build

A shell command that runs the build of the given target

clean

A shell command that erases all files produced by the build command

task

A character vector of parent task names. The mechanism of tasks allows to group rules. Anything different from 'all' will cause creation of a new task depending on the given rule. Executing make taskname will then force building of this rule.

phony

Whether the rule has a PHONY (i.e. non-file) target. A rule should be marked with phony if the target is not a file name that would be generated by the build commands. E.g. all or clean are phony targets. Also all targets representing tasks (see task above) are phony.

type

A string representing a type of a rule used e.g. while printing a rule in easily readable format. For instance, rRule() uses R, markdownRule() uses markdown etc.

Value

Instance of S3 class rmake.rule

Details

If there is a need to group some rules together, one can assign them the same task identifier in the task argument. Each rule may get assigned one or more tasks. Tasks may be then built by executing make task_name on the command line, which forces to rebuild all rules assigned to the task 'task_name'. By default, all rules are assigned to task all, which causes make all command to build everything.

Examples

Run this code

# NOT RUN {
r <- rule(target='something.abc',
          depends=c('file.a', 'file.b', 'file.c'),
          build='myCompiler file.a file.b file.c -o something.abc',
          clean='$(RM) something.abc')

# generate the content of a makefile (as character vector)
makefile(list(r))

# generate to file
tmp <- tempdir()
makefile(list(r), file.path(tmp, "Makefile"))
# }