A CIL Tutorial - Department of Computer Science - ETH Zürich

CHAPTER 14. IMPLEMENTING A SIMPLE DSL 122
(L.map (fun a → (a.argVi.vname¢"addr"), Fe (AddrOf(var a.argVi))) al)@
(L.map (fun a → (a.argVi.vname¢"l"), Fl(var a.argVi)) al)@
(L.map (fun a → (a.argGot.vname), Fl(var a.argGot)) al))
The function initArgs generates statements that initialize the global variables for arguments with
their default values.
let initArgs (al : argument list) : stmt list =
L.map (fun a → i2s(Set(var a.argVi, a.argDef, locUnknown))) al
The function printHelp generates statements using printf that print the help text for the arguments
to standard out. The help text gives the short version, the long version, the default value,
and tells whether the argument is mandatory. The statements generated by printHelp will be used
in case some checks on the runtime argument values fails.
let printHelp (f : file) (al : argument list) : stmt list =
let print = findOrCreateFunc f "printf" intType in
let s s = mkString s in
[i2s(Call(None, v2e print, [s "Improper arguemnts\n"], locUnknown))]@
(L.map (fun a →
let af = if a.argFmt ≠ "" then a.argFmt else "%d" in
let fmt = if a.argOpt
then s ("\t-%s,--%s\t%s ("¢af¢")\n")
else s "\t-%s,--%s\t%s (mandatory)\n"
in
let args = if a.argOpt
then [fmt; s a.argShort; s a.argName; s a.argHelp; a.argDef]
else [fmt; s a.argShort; s a.argName; s a.argHelp]
in
i2s (Call(None, v2e print, args, locUnknown))
) al) @
[mkStmt (Return(Some mone, locUnknown))]
The function makeArgChecks generates an if statement that checks two things. First, it checks that
all mandatory arguments have been given. Second, it checks that all assertions stipulated by the
programmer on the arguments are true. If either of these fails, the statements given by printHelp
are used to print the help messages, and exit from the program with a failure code.