gen_iocsh_reg.pl

[Benjamin Franksen via Tech-talk <tech-talk@aps.anl.gov>]

I recently wrote this little perl script (attached) to automate the
writing of iocsh registration code using a trivial but (I think)
complete declarative specification "language" that is easy to compose on
the command line or in a Makefile. I am posting the code and an example
of what it does in the hope that it may turn out to be useful for others.

Here is the help output (slightly re-formatted for this email):

"""
> gen_iocsh_reg.pl -h
Usage: gen_iocsh_reg.pl [REG=<registrar>] <command>=[<args>] ...
where
  <registrar> is the name of a C function to register the commands (if
    not specified you'll have to call iocshRegister yourself for each
    command)
  <command> is the name of a command (in C as well as in the shell)
  <args> is a comma separated list of argument descriptions <arg>
  <arg> describes an argument to the underlying C command and is either
    * a constant literal value (for instance 0 or "a string"), or
    * an iocsh argument description of the form <name>:<type> (for
      instance card_number:Int) where <type> is one of {Int, Double,
      String}.
Only arguments of the <name>:<type> sort are exposed as arguments to the
command in the shell.
"""

Here is a real-world example use case,. This is from a Makefile in one
of our projects:

"""
iocshExtra.c:
        $(PERL) $(BII_SCRIPTS_BIN)/gen_iocsh_reg.pl REG=registerIocshExtra\
         asDump=0,0,verbosity:Int \
         bootShow= bootChange= \
         gevShow= gevDelete=name:String
gevUpdate=name:String,value:String > $@
"""

From this it generates the following boilerplate code:

"""
/*
 * IOC shell command registration
 */

#include "epicsExport.h"
#include "iocsh.h"

static const iocshArg asDumpArg0 = { "verbosity", iocshArgInt };
static const iocshArg *const asDumpArgs[] = {
    &asDumpArg0
};
static const iocshFuncDef asDumpDef = {"asDump", 1, asDumpArgs};
static void asDumpWrapper(const iocshArgBuf *args) {
    asDump(0, 0, args[0].ival);
}

static const iocshArg *const bootChangeArgs[] = {};
static const iocshFuncDef bootChangeDef = {"bootChange", 0, bootChangeArgs};
static void bootChangeWrapper(const iocshArgBuf *args) {
    bootChange();
}

static const iocshArg *const bootShowArgs[] = {};
static const iocshFuncDef bootShowDef = {"bootShow", 0, bootShowArgs};
static void bootShowWrapper(const iocshArgBuf *args) {
    bootShow();
}

static const iocshArg gevDeleteArg0 = { "name", iocshArgString };
static const iocshArg *const gevDeleteArgs[] = {
    &gevDeleteArg0
};
static const iocshFuncDef gevDeleteDef = {"gevDelete", 1, gevDeleteArgs};
static void gevDeleteWrapper(const iocshArgBuf *args) {
    gevDelete(args[0].sval);
}

static const iocshArg *const gevShowArgs[] = {};
static const iocshFuncDef gevShowDef = {"gevShow", 0, gevShowArgs};
static void gevShowWrapper(const iocshArgBuf *args) {
    gevShow();
}

static const iocshArg gevUpdateArg0 = { "name", iocshArgString };
static const iocshArg gevUpdateArg1 = { "value", iocshArgString };
static const iocshArg *const gevUpdateArgs[] = {
    &gevUpdateArg0,
    &gevUpdateArg1
};
static const iocshFuncDef gevUpdateDef = {"gevUpdate", 2, gevUpdateArgs};
static void gevUpdateWrapper(const iocshArgBuf *args) {
    gevUpdate(args[0].sval, args[1].sval);
}

static void registerIocshExtra(void) {
    static int firstTime = 1;
    if (firstTime) {
        firstTime = 0;
        iocshRegister(&asDumpDef, asDumpWrapper);
        iocshRegister(&bootChangeDef, bootChangeWrapper);
        iocshRegister(&bootShowDef, bootShowWrapper);
        iocshRegister(&gevDeleteDef, gevDeleteWrapper);
        iocshRegister(&gevShowDef, gevShowWrapper);
        iocshRegister(&gevUpdateDef, gevUpdateWrapper);
    }
}
epicsExportRegistrar(registerIocshExtra);
"""

Cheers
Ben

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