MPE/iX Commands Reference Manual > Appendix B Expression Evaluator Functions

Appendix B Expression Evaluator Functions

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Expression Evaluator Features

Ord
Strings
Variables
Variables and Strings

The expression evaluator is a system procedure used by the user interface to accept a string, number, or Boolean expression, evaluate it, and return the result. This procedure is used by the CALC, SETVAR, IF, ELSEIF, and WHILE commands and within a ![ ]..

The expression evaluator provides the following:

consistent evaluation of expressions
compatibility with MPE V/E job control word evaluation
user flexibility

The expression evaluator uses algebraic notation and supports the functions defined in Table B-1 "Expression Evaluator Functions". The references that appear in this table in parentheses, for example (8), are defined following the table.

See HELP for description of new functions and examples.

E.g. HELP FSYNTAX

Table B-1 Expression Evaluator Functions

Symbol	Function	Example	Result
+(numeric)	addition	4 + 5	9
+(string)	concatenate	"abc' + "de'	abcde
-(numeric)	subtraction	12 - 6	6
-(string)	deletion of first occurrence	"abc' - "b'	ac
*	multiplication	4 * 5	20
/	integer division	79/ 10	7
^	exponentiation (9)	2^3	8
either " or '	string identifier	either "abc' or "abc'	abc
()	parentheses	(3 + 4) * 2	14
<	less than (1)	5 < 6	TRUE
<=	less than or equal (1)	"abc' <= "abc'	TRUE
>	greater than (1)	"xyz' > "abc'	TRUE
>=	greater than or equal (1)	"abc'>= "abc'	TRUE
<>	not equal	5 <> 6	TRUE
=	equal	"xyz"= "xyz"	TRUE
ABS(`integer`)	absolute value	abs(-4)	4
ALPHA(`string`)	check if a string is alphabetic	alpha('abcd') alpha('ab3d ef')	TRUE FALSE
ALPHANUM(`string`)	check if a string is only alphabetics and digits	alphanum('abCd') alphanum('45abd') alphanum('3def')	TRUE TRUE FALSE
AND	logical and	7=7 and 5=5	TRUE
ANYPARM
BAND	bitwise and	7 band 13	5
BASENAME (`string`)	returns the filename component	CALC basename ('a.b.c') CALC basename ('/a/b/c') CALC basename ('./a/b') CALC basename ("./a.sl",".sl") CALC basename ('/') CALC basename ("*feq") CALC basename ('$null') CALC basename ('abc.g','c') CALC basename (/usr/lib/liby.a','.a') CALC basename ('/usr/lib/liby.a','liby.a'	A c b a / *FEQ $NULL AB liby liby.a
BNOT	bitwise not	bnot 5	-6
BOR	bitwise or	5 bor 2	7
BOUND(`varname`)	variable definition test (2)	bound(`HPPATH`)	TRUE
BXOR	bitwise exclusive or	7 bxor 5	2
CHR(`integer`)	ASCII value (integer) ===> character	chr(65)	A
CSL	circular shift left (3)	-2 csl 2	-5
CSR	circular shift right (3)	-7 csr 1	-4
DECIMAL(`string`)	returns a string value of an integer	CALC decimal (255) CALC len(decimal($ff)) setvar i 0 while setvar(i,i+1) < 10 and finfo("FILE"+DECIMAL(I), 'exists') do ...	255 3, $3, %3
DELIMPOS(`str` [,`delims`] [,`nth`] [,`start`])	returns index in `str` of the `nth` delimiter beginning at `start`; default `delims` are a space, a comma, a semicolon, an equals sign, left and right parentheses, left and right brackets, single quote, double quote, and Tab; default `nth` is 1; default `start` is 1	DELIMPOS('file a=bb, old;rec=40,,f,ascii')	5
DIRNAME(`string`)	returns dirctory components of a filename
DWNS(`string`)	shift string to lowercase (7)	dwns('aBC&#dE')	abc&#de
EDIT(`string, editstr` [,`start`])	performs full `REDO`-like editing of a string	EDIT(`abcdefg','>dd') EDIT('ab cd;g', 'dwd')	'abce' 'cd;g'
FINFO(`filename, option`)	file information (6)	FINFO('x.pub',0)	TRUE
FQUALIFY(`string`)	returns a fully qualified filename	CALC fqualify('a') CALC fqualify('a.b') CALC fqualify('a.b.c') CALC fqualify('./a') CALC fqualify('./A') CALC fqualify('/a/b/c') CALC fqualify('*a') CALC fqualify('$null') CALC dirname (fqualify('./a'))	A.GROUP.ACCOUNT # when the CWD is your logon group or /CWD/A #when the CWD is a directory A.B.ACCOUNT A.B.C /ACCOUNT/GROUP/a A.GROUP.ACCOUNT # when the CWD is your logon group or /CWD #when the CWD is a directory /a/b/c A $NULL /ACCOUNT GROUP # when the CWD is your logon group or CWD # when the CWD is a directory
FSYNTAX()(`string`)	returns the syntax of the passed filename argument	fsyntax('a.b.c') fsyntax('/a/b/c') fsyntax('./ab@/c') fsyntax($null') fsyntax('a.b.c.d')	MPE POSIX POSIX;WILD MPE;$FILE MPE ERROR=426
HEX(`integer`)	convert to hexadecimal string	hex(329)	$149
INPUT([`prompt`] [,`wait`])	accept user input (10)	input('Enter choice:',20)	Enter choice: `Y`Return "`Y`"
LEN(`string`)	string length	len("abc')	3
LFT(`string, # chars`)	left string extraction	lft('abc',2)	ab
LSL	logical shift left	7 lsl 1	14
LSR	logical shift right	-7 lsr 1	2,147,483,644
LTRIM(`string` [,`trimstr`])	trim left end of string (11)	'X'+ltrim(' abc') "X"+ltrim('...abc', '.')	Xabc Xabc
MAX(`num1` [,`num2`...])	find largest of several integers	max(5,4-3,70,0)	70
MIN(`num1` [,`num2`...])	find smallest of several integers	min(5,4,-3,70,0)	-3
MOD	modulo (4)	25 mod 2	1
NOT	logical not	not(2>1)	FALSE
NUMERIC(`string`)	check if a string is all digits	numeric('12345') numeric('$a234ef')	TRUE FALSE
OCTAL(`integer`)	convert to octal string	octal(329)	%511
ODD(integer)	determine if integer is odd	odd(233) odd(-2)	TRUE FALSE
OR	logical or	5=5 or 2=3	TRUE
ORD(`string`)	ordinal (8)	ord('AbcD')	65
POS(`find-str, source-str` [,`n`])	find `nth` occurrence of `find str` in `source str`; positive value for `n` begins search at left; negative value for `n` begins search at right) (12)	pos('ab','cgabd') pos('.','file.grp.acct',2) pos('.','file.grp.acct',-1)	3 9 9
PMATCH(`pattern, str` [,`start`])	searches for `pattern` in a given string (`str`) starting at `start`; `pattern` may contain wildcards; default `start` is 1	PMATCH('f@','fread') PMATCH('abc','abcd')	TRUE FALSE
REPL(`str, oldstr, newstr` [,`cnt`] [,`start`])	in a given string (`str`), replaces `cnt` occurrences of `oldstr` with `newstr`, beginning at `start`; if `cnt` is positive, replacement begins at the left end of `str`; if negative, replacement begins at the right end of `str`; default `start` is 1; default `cnt` is zero (meaning all occurences)	REPL('aaabcaab','aa','X') REPL('aaabcaab','ab','',-1)	'XabcXb' 'aaabca'
RHT(`string, # chars`)	right string extraction	rht("abc',2)	bc
RPT(`string, count`)	repeat a string (-count reverses string)	rpt('aBc',3) rpt('aBc',-3)	aBcaBcaBc cBacBacBa
RTRIM(`string` [,`trimstr`])	trim right end of string (11)	rtrim('abc ')+'X' rtrim('abc...','.')+"X"	abcX abcX
SETVAR(`varname, expr`)	return result of `expr` and set `varname` to result (13)	setvar(`myvar`,2*3+5)	sets variable `myvar` to 11 and returns 11
STR(`string, start-pos, # chars`)	general string extraction	str('abcde',2,3)	bcd
TYPEOF(`expression`)	type of variable or expression (5)	typeof(`HPPATH`)	2 (string)
UPS(`string`)	shift string to uppercase (7)	ups('aBc5d')	ABC5D
WORD(`string` [,`delims`] [,`nth`] [,`end_var`] [,`start`])	performs general word extraction; default `delims` are a space, a comma, a semicolon, an equals sign, left and right parentheses, left and right brackets, single quote, double quote, and Tab; default `nth` is 1; the default `end_var` is no variable; the default `start` is 1	WORD('file a=bb,old; rec=40,,f,ascii') WORD('file a=bb,old; rec=40,,f,ascii',,-4,j)	'file' '40', j=18
XOR	logical exclusive or	7=7 xor 5=5	TRUE
XWORDstring)	returns a string less 'word'	xword('file a=bb, old; rec=40, ,f, ascii') xword('file a=bb, old; rec=40, ,f, ascii' , ,2) xword('file a=bb, old; rec=40, ,f, ascii' , " ; , " , , j, 8) xword('file a=bb, old; rec=40, ,f, ascii' , , -4, j)	'a=bb,old;rec=40, , f, ascii' 'file bb, old; rec=40 , , f, ascii' 'file a=old; rec=40 , ,f , ascii' and J=10 'file a=bb, old;rec=, f, ascii ' and J=18

Appendix A Predefined Variables in MPE/iX

References

Appendix B Expression Evaluator Functions

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