zc.recipe.macro 1.2.0

Basic Use

In the most basic use of a macro, a section invokes the macro on itself, and uses itself as the parameter provider:

[buildout] parts = hard-rocker

[rock] question = Why do I rock $${:rocking-style}?

[hard-rocker] recipe = zc.recipe.macro macro = rock rocking-style = so hard

This will result in:

[hard-rocker]
recipe = zc.recipe.macro:empty
question = Why do I rock so hard?
rocking-style = so hard

The recipe gets changed to zc.recipe.macro:empty, which is a do nothing recipe, because the invoking secion must be a part in order to execute recipes, and buildout demands that parts have a recipe, so it couldn’t be emptied.

Default Values

It is possible to include default values for parameters in a macro, like so:

[rock]
question = Why do I rock $${:rocking-style}?
rocking-style = so hard

Creating Parts

Of course, there wouldn’t much point to this if one could only create sections with a dummy recipe. This is where the result-recipe option comes in:

[buildout]
parts = hard-rocker

[rock]
question = Why do I rock $${:rocking-style}?

[hard-rocker]
recipe = zc.recipe.macro
macro = rock
result-recipe = zc.recipe.its_still_rock_n_roll_to_me
rocking-style = so hard

That will result in:

[hard-rocker]
recipe = zc.recipe.its_still_rock_n_roll_to_me
question = Why do I rock so hard?
rocking-style = so hard

Targets

Often, one wants to create multiple new sections. This is possible with the targets option. This is only useful, however, if one can provide multiple sources for parameters. Fortunately, you can. Each new section can optionally be followed by a colon and the name of a section to use for parameters:

[buildout]
parts = rockers

[rock]
question = Why do I rock $${:rocking-style}?

[hard-rocker-parameters]
rocking-style = so hard

[socks-rocker-parameters]
rocking-style = my socks

[tired-rocker-parameters]
rocking-style = all night

[rockers]
recipe = zc.recipe.macro
macro = rock
targets =
    hard-rocker:hard-rocker-parameters
    socks-rocker:socks-rocker-parameters
    rocking-style:tired-rocker-parameters

That will generate these rockers:

[hard-rocker]
recipe = zc.recipe.macro:empty
question = Why do I rock so hard?

[socks-rocker]
recipe = zc.recipe.macro:empty
question = Why do I rock my socks?

[tired-rocker]
recipe = zc.recipe.macro:empty
question = Why do I rock all night?

Special Variables

zc.recipe.macro uses __name__ to mean the name of the section the macro is being invoked upon. This allows one to not know the name of particular section, but still use it in output:

[buildout]
parts = rockers

[rock]
question = Why does $${:__name__} rock $${:rocking-style}?

[hard-rocker-parameters]
rocking-style = so hard

[socks-rocker-parameters]
rocking-style = my socks

[tired-rocker-parameters]
rocking-style = all night

[rockers]
recipe = zc.recipe.macro
macro = rock
targets =
    hard-rocker:hard-rocker-parameters
    socks-rocker:socks-rocker-parameters
    rocking-style:tired-rocker-parameters

This will result in rockers like these:

[hard-rocker]
recipe = zc.recipe.macro:empty
question = Why does hard-rocker rock so hard?

[socks-rocker]
recipe = zc.recipe.macro:empty
question = Why does socks-rocker rock my socks?

[tired-rocker]
recipe = zc.recipe.macro:empty
question = Why does tired-rocker rock all night?