KeyMap: A Hierarchical Key-Value Store for GNU Make

This library implements a hierarchical key-value store for GNU Make. It allows the user to:

• Map keys to values.
• For a given key prefix, list all valid next key components.

Usage

Place key-value pairs in a file (see SAMPLE_KEYS), one per line:

program_option|opt_1          --fast
program_option|opt_2          --very --accurate
reference|human|url           ftp://example.com/human.fa.gz
reference|human|md5sum        012345
reference|ecoli|url           ftp://example.com/ecoli.fa.gz
reference|human|md5sum        012345
dataset|human_1|url           ftp://example.com/human_1.tar.gz
dataset|human_1|md5sum        012345
dataset|human_1|reference     human
dataset|human_2|url           ftp://example.com/human_2.tar.gz
dataset|human_2|md5sum        012345
dataset|human_2|reference     human
dataset|ecoli_1|url           ftp://example.com/ecoli_1.tar.gz
dataset|ecoli_1|md5sum        012345
dataset|ecoli_1|reference     ecoli

Note:

• Everything up to the first whitespace is interpreted as the key.
• Everything after the first whitespace is interpreted as the value.
• The value may contain whitespace, but multiple consecutive spaces (including tabs) will be converted to a single space. (The lines are passed through awk.)
• Keys may include a key spearator (by default, |).
• The keys will be stored in GNU Make variables, and as such, they may not include: :, #, ===, or whitespace. See: Make Variables.
• Do not use keys which end in a separator (e.g., dataset|). These are used internally to store valid next key components.

Load the key-value pairs in GNU Make:

KEYMAP_FILES = SAMPLE_KEYS
include /path/to/keymap.make

Retrieve value for a given key with keymap_val:

human.fa:
	wget $(call keymap_val,reference|human|url) -O- | gunzip >$@

Retrieve list of next key components for a given prefix with keymap_key_list:

define process_dataset
# ${1} = dataset
# ${2} = reference
...
endef
# ds = human_1 human_2 ecoli_1
# ref = human human ecoli
$(foreach ds,$(call keymap_key_list,dataset),\
$(foreach ref,$(call keymap_val,dataset|${ds}|reference),\
$(eval $(call process_dataset,${ds},${ref}))))

Influential Variables

These GNU Make variables should be set prior to including keymap.make.

KEYMAP_FILES

List of files containing key-values. Key-value pairs in later files override pairs (with the same key) in earlier files. If KEYMAP_FILES is not specified, keys will be loaded from KEYS and KEYS.local if they exist in the current directory.

KEYMAP_SEPARATOR

Key component separator. By default, |.

KEYMAP_PREFIX

Prefix added to all keys when storing them as GNU Make variables. By default, KEYMAP.

Example

For an example Makefile using the keys above, see sample.make. Run with make -f sample.make.

License

Released under the MIT license.