zc.recipe.macro 1.3.0

Macro-recipe for buildout.

Macro Quickstart

zc.recipe.macro is a set of recipes allowing sections, or even parts, to be created dynamically from a macro section and a parameter section. This enables the buildout to keep its data seperate from its output format.

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:

[buildout]
parts = hard-rocker

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

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

Result:

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

Buildout:

[buildout]
parts = hard-rocker

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

[hard-rocker]
recipe = zc.recipe.macro
macro = rock

Result:

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

[buildout]
parts = hard-rocker

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

[hard-rocker]
recipe = zc.recipe.macro
result-recipe = zc.recipe.macro:test1
macro = rock
rocking-style = so hard

Result:

[hard-rocker]
recipe = zc.recipe.macro:test1
result-sections = hard-rocker
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:

[buildout]
parts = rockers hard-rocker socks-rocker tired-rocker

[rock]
question = Why do I rock $${:rocking-style}?
rocking-style = $${: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
result-recipe = zc.recipe.macro:empty
macro = rock
targets =
    hard-rocker:hard-rocker-parameters
    socks-rocker:socks-rocker-parameters
    tired-rocker:tired-rocker-parameters

Result:

[rockers]
recipe = zc.recipe.macro:empty
result-sections = hard-rocker socks-rocker tired-rocker

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

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

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

In the previous example we hardcoded the result parts after the invoker in ${buildout:parts}. This is brittle, because someone might change the names of the targets or alphabetize the parts list. An invocation will have a list of the sections it modified in its result-sections variable, which is created when the macro is executed.

Buildout:

[buildout]
parts = ${rockers:result-sections}

[rock]
question = Why do I rock $${:rocking-style}?
rocking-style = $${: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
result-recipe = zc.recipe.macro:test1
macro = rock
targets =
    hard-rocker:hard-rocker-parameters
    socks-rocker:socks-rocker-parameters
    tired-rocker:tired-rocker-parameters

Result:

[rockers]
result-sections = hard-rocker socks-rocker tired-rocker

[hard-rocker]
question = Why do I rock so hard?
recipe = zc.recipe.macro:test1
rocking-style = so hard

[socks-rocker]
question = Why do I rock my socks?
recipe = zc.recipe.macro:test1
rocking-style = my socks

[tired-rocker]
question = Why do I rock all night?
recipe = zc.recipe.macro:test1
rocking-style = all night

Order of Precedence for Recipes for Result Sections

The source for the recipe option for result sections has a particular precedence, as follows:

1) recipe in the parameters section of the macro target
2) result-recipe in the parameters section for the macro target
3) result-recipe in the macro invocation
4) recipe in the macro definition

The following tests will illustrate these rules, starting with rule 4 and building up.

In the following buildout, rock:recipe will be used in the [hard-rockers] section as the recipe, because of rule 4. Buildout:

[buildout]
parts = rockers

[rock]
question = Why do I rock $${:rocking-style}?
rocking-style = $${:rocking-style}
recipe = zc.recipe.macro:test4

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

[rockers]
recipe = zc.recipe.macro
macro = rock
targets = hard-rocker:hard-rocker-parameters

Result:

[hard-rocker]
question = Why do I rock so hard?
recipe = zc.recipe.macro:test4
rocking-style = so hard

In the following buildout, ${rockers:result-recipe} will be used because of rule 3. Buildout:

[buildout]
parts = rockers

[rock]
question = Why do I rock $${:rocking-style}?
rocking-style = $${:rocking-style}
recipe = zc.recipe.macro:test4

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

[rockers]
recipe = zc.recipe.macro
result-recipe = zc.recipe.macro:test3
macro = rock
targets = hard-rocker:hard-rocker-parameters

Result:

[hard-rocker]
question = Why do I rock so hard?
recipe = zc.recipe.macro:test3
rocking-style = so hard

In the following buildout, ${hard-rocker-paramers:result-recipe} will be used because of rule 2. Buildout:

[buildout]
parts = rockers

[rock]
question = Why do I rock $${:rocking-style}?
rocking-style = $${:rocking-style}
recipe = zc.recipe.macro:test4

[hard-rocker-parameters]
result-recipe = zc.recipe.macro:test2
rocking-style = so hard

[rockers]
recipe = zc.recipe.macro
result-recipe = zc.recipe.macro:test3
macro = rock
targets = hard-rocker:hard-rocker-parameters

Result:

[hard-rocker]
question = Why do I rock so hard?
recipe = zc.recipe.macro:test2
rocking-style = so hard

In the following buildout, ${hard-rocker-parameters:recipe} will be used because of rule 1. Buildout:

[buildout]
parts = rockers

[rock]
question = Why do I rock $${:rocking-style}?
rocking-style = $${:rocking-style}
recipe = zc.recipe.macro:test4

[hard-rocker-parameters]
recipe = zc.recipe.macro:test1
result-recipe = zc.recipe.macro:test2
rocking-style = so hard

[rockers]
recipe = zc.recipe.macro
result-recipe = zc.recipe.macro:test3
macro = rock
targets = hard-rocker:hard-rocker-parameters

Result:

[hard-rocker]
question = Why do I rock so hard?
recipe = zc.recipe.macro:test1
rocking-style = so hard

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:

[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
result-recipe = zc.recipe.macro:empty
macro = rock
targets =
    hard-rocker:hard-rocker-parameters
    socks-rocker:socks-rocker-parameters
    tired-rocker:tired-rocker-parameters

Result:

[rockers]
recipe = zc.recipe.macro:empty
result-sections = hard-rocker socks-rocker tired-rocker

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

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

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

CHANGES

1.3.0 (2009-07-22)

• The recipe option for result sections is now pulled from the following sources, in this order:

  1. recipe in the parameters section of the macro target

  2. result-recipe in the parameters section for the macro target

  3. result-recipe in the macro invocation

  4. recipe in the macro definition

• Correct a rest error, that prevent the package of being installed with docutils 0.4.

1.2.5 (2009-03-05)

• Removed version sections from the documentation.

• Improved test coverage.

• Put QUICKSTART.txt under test, using manuel.

• Macro invocations will grow a result-sections value that lists the sections they modified or created.

• README.txt is now mostly Manuellified.

1.2.4 (2008-07-18)

• Fixed a bug that made self-targetting invocations fail when the macro utilized default values and the option that read the default came out the Options iteration first, added a regression test.

• Changed the test setup so that buildouts are tested by calling methods rather than creating a subprocess. This allows for the –coverage flage to work in bin/test, and makes debugging and mimmicking the test output significantly easier.

• Fixed addition of targets so that they will show up properly when one calls buildout.keys().

1.2.3 (2008-07-11)

• Fixed a bug in the CHANGES ReST

1.2.2 (2008-07-11)

• Fixed a bug in setup.py where setuptools was not being imported

• Changed date format in CHANGES.txt to YYYY-MM-DD

1.2.1 (2008-07-10)

• Fixed a typo in the quickstart

1.2.0 (2008-07-10)

• First release