How to get started with gnet-makefile and gschem.
Type "gschem Makefile.sch" to take a peek at the flow. To get started, you'll
need to type "./makebootstrap.sh" to make this into a Makefile. Note that you
don't have to do this again in this project: once you have the initial Makefile
you may modify Makefile.sch as needed. Make will figure out when it needs to
update Makefile.
Now, just type "make". Since the schematics don't exist, make will launch gschem
to create example.1.sch. As of 1.8 gschem is a bit clumsy when creating a new
file, sorry. Enter some circuitry for this page, save it, and quit gschem. Make
will then launch gschem to create example.2.sch. Once you've saved and quit,
make will launch gnetlist twice, creating example.net and example.parts.txt.
Flows consist of alternating files and rules. Files are passive, rules read and
write. Pins on the symbols have arrows indicating flow direction. Files have
writers and readers, rules have prerequisites and targets. A file with no writer
must be created outside the flow (make will complain if it doesn't exist). A
file with no reader is an endpoint, and since no rule will have have it as a
prerequisite, the only way to make it is to ask for it explicitly from the
command line. A rule must have at least one target (output) but needs no
prerequisites.
The device= attribute controls the role of a symbol.
device=makefile-prolog
device=makefile-epilog
Symbols of this type just hold literal text in the value= attributes. The text
is placed at the beginning or end of the Makefile.
device=makefile-rule
Symbols of this type represent rules. They have pins of
pintype=from-prerequisites and pintype=to-target. They generally have a recipe=
attribute holding a shell script that preforms the prequisite-to-target
transformation.
device=makefile-command
A special case of a rule. These symbols represent named targets that are not
actual files ("phony targets" in make jargon). So, these have no to-target pin.
The target is given in the value= attribute. With no recipe, a command just
triggers the construction of its prerequisites. Use a recipe= attribute for a
command that does something (like an interactive simulation) but has no output
that is part of the flow.
device=file
Symbols of this type represent files. They may represent multiple files:
gnet-makefile creates the list from all source= and file= attributes attached to
the refdes. It's handy to use source= for schematics and file= for others: this
makes hierarchy navigation in gschem work right with Makefile schematics.
Todo:
Need a way to find and represent indirect prerequisites ("make depend").
Need a "one-way" combiner for end points like "make clean".