Args.mesa
Copyright © 1985 by Xerox Corporation. All rights reserved.
Bloomenthal, March 21, 1986 4:11:45 pm PST
DIRECTORY Commander, Rope;
Args: CEDAR DEFINITIONS
~ BEGIN
Arg: TYPE ~ RECORD [ok, bool: BOOL ← FALSE, int: INT ← 0, real: REAL ← 0.0, rope: Rope.ROPE ← NIL];
NArgs: PROC [cmd: Commander.Handle] RETURNS [INTEGER];
Number of command line arguments (does not count argv[0]).
GetRope: PROC [cmd: Commander.Handle, nArg: INTEGER ← 0] RETURNS [Rope.ROPE];
Return argument nArg as a rope.
ArgRope: PROC [cmd: Commander.Handle, nArg: INTEGER ← 0] RETURNS [Arg];
Return rope of argument nArg as an Arg.
ArgReal: PROC [cmd: Commander.Handle, nArg: INTEGER ← 0] RETURNS [Arg];
Return real of argument nArg
ArgInt: PROC [cmd: Commander.Handle, nArg: INTEGER ← 0] RETURNS [Arg];
Return integer of argument nArg
ArgIntDef: PROC [cmd: Commander.Handle, nArg: INTEGER ← 0, defVal: INT] RETURNS [Arg];
Return integer of argument nArg if it exists, else return the default value.
ArgIntRange: PROC [cmd: Commander.Handle, n, min, max: INT] RETURNS [Arg];
arg.ok is true iff argument exists, is integer, and within specified range.
ArgsGet: PROC [cmd: Commander.Handle, fmt: Rope.ROPE]
RETURNS [BOOL, Arg, Arg, Arg, Arg, Arg, Arg, Arg, Arg, Arg, Arg, Arg, Arg];
ArgsGet returns a boolean and 12 args; each return arg has a boolean, integer, real, and
rope field. The return boolean is true iff all argument conversions are performed correctly.
fmt specifies the types of conversions to occur when parsing the commander argument list.
fmt syntax consists of a type delimiter and argument specifier.
Type delimiters within fmt are:
[    any following argument symbols are optional
%    any following argument symbols are required
-    any following arguments are required only if a key is specified
Argument specifiers within fmt are:
i    an integer argument is expected
r    a real argument is expected
s    a string argument is expected
fmt examples:
"-pVal%i" if "-pVal" is an argument, an integer is expected to follow immediately.
"-f%b"  if "-f" is an argument, the boolean field of its return Arg is set true.
"%iir"   two integers and one real are expected as arguments.
A hyphenated type delimiter uniquely identifies itself and is allowed to appear in any order
within the argument list. Because of this, the argument list is scanned first for hyphenated
type delimiters and their arguments. A second scan is performed in which non-hyphenated
type delimiters are matched with the remaining arguments.
Conversion examples:
ok: BOOL;
arg1, arg2, arg3, arg4: Arg;
[ok, arg1, arg2, arg3, arg4] ← ArgsGet[cmd, "%is-x%r-q%b"];
First, the commander argument list is searched for a "-x." If found, a real should be the
next commander argument and arg3.int is set equal to it. Te argument list is next searched
for a "-q;" if found arg4.bool is set true. After this, an integer argument must remain and
is used to set arg1.int, and a string argument must remain and is used to set arg2.rope.
For the above example, the following inputs all produce proper conversion (ok = TRUE):
Program 3 name -q
TRUE: arg1.ok, arg2.ok, arg4.ok; FALSE: arg3.ok;
arg1.int = 3; arg2.rope = name; arg4.bool = TRUE.
Program -x 2.4 3 name
TRUE: arg1.ok, arg2.ok, arg3.ok; FALSE: arg4.ok;
arg1.int = 3; arg2.rope = name; arg3.real = 2.4.
Program 3 name
TRUE: arg1.ok, arg2.ok; FALSE: arg3.ok, arg4.ok;
arg1.int = 3; arg2.rope = name.
Program -q 3 -x 2.4 name
TRUE: arg1.ok, arg2.ok, arg3.ok, arg4.ok;
arg1.int = 3; arg2.rope = name; arg3.real = 2.4; arg4.bool = TRUE.
The following inputs all produce improper conversion (ok = FALSE):
Program 3 -q
TRUE: arg1.ok, arg4.ok; FALSE: arg2.ok, arg3.ok;
arg1.int = 3; arg4.bool = TRUE.
Program -x name
FALSE: arg1.ok, arg2.ok, arg3.ok, arg4.ok.
Program -x 1 3 name
FALSE: arg3.ok, arg4.ok; TRUE: arg1.ok, arg2.ok;
arg1.int = 3; arg2.rope = name.
Program 3 name -q 2.4
TRUE: arg1.ok, arg2.ok, arg4.ok; FALSE: arg3.ok;
arg1.int = 3; arg2.rope = name; arg4.bool = TRUE;
END.