fmlexpr(1F)							   FMLI Commands						       fmlexpr(1F)

NAME

       fmlexpr - evaluate arguments as an expression

SYNOPSIS

       fmlexpr arguments

DESCRIPTION

       The fmlexpr function evaluates its arguments as an expression. After evaluation, the result is written on the standard output. Terms of the
       expression must be separated by blanks. Characters special to FMLI must be escaped. Note that  30 is returned to  indicate  a  zero  value,
       rather  than  the null string. Strings containing blanks or other special characters should be quoted. Integer-valued arguments may be pre-
       ceded by a unary minus sign. Internally, integers are treated as 32-bit, 2s complement numbers.

       The operators and keywords are listed below. Characters that need to be escaped are preceded by . The  list  is  in  order  of	increasing
       precedence, with equal precedence operators grouped within {} symbols.

USAGE

   Expressions
       expr | expr

	   Returns the first expr if it is neither  NULL nor 0, otherwise returns the second expr.

       expr & expr

	   Returns the first expr if neither expr is  NULL or 0, otherwise returns 0.

       expr { =, >, >=, <, <=, != } expr

	   Returns the result of an integer comparison if both arguments are integers, otherwise returns the result of a lexical comparison.

       expr { +, - } expr

	   Addition or subtraction of integer-valued arguments.

       expr { *, /, % } expr

	   Multiplication, division, or remainder of the integer-valued arguments.

       expr : expr

	   The	matching  operator  :  (colon)	compares  the  first argument with the second argument which must be a regular expression. Regular
	   expression syntax is the same as that of ed(1), except that all patterns are "anchored" (that is, begin with ^) and,  therefore,  ^	is
	   not	a special character, in that context. Normally, the matching operator returns the number of bytes matched (0 on failure). Alterna-
	   tively, the (...) pattern symbols can be used to return a portion of the first argument.

EXAMPLES

       Example 1 Incrementing a variable

       Add 1 to the variable a:

	 example% fmlexpr $a + 1 | set -l a

       Example 2 Setting a variable equal to a filename

       For $a equal to either /usr/abc/file or just file:

	 example% fmlexpr  $a  :   .*/(.*)  |  $a

       returns the last segment of a path name (that is, file). Watch out for / alone as an argument: fmlexpr will take it as the division  opera-
       tor (see NOTES below).

       Example 3 A better representation of Example 2

	 example% fmlexpr  //$a  :  .*/(.*)

       The  addition  of  the // characters eliminates any ambiguity about the division operator (because it makes it impossible for the left-hand
       expression to be interpreted as the division operator), and simplifies the whole expression.

       Example 4 Counting characters in a variable

       Return the number of characters in $VAR:

	 example% fmlexpr $VAR : .*

EXIT STATUS

       As a side effect of expression evaluation, fmlexpr returns the following exit values:

       0    if the expression is neither NULL nor 0 (that is, TRUE)

       1    if the expression is NULL or 0 (that is, FALSE)

       2    for invalid expressions (that is, FALSE).

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ed(1), expr(1), set(1F), sh(1), attributes(5)

DIAGNOSTICS

       syntax error	       for operator/operand errors

       non-numeric argument    if arithmetic is attempted on such a string

       In the case of syntax errors and non-numeric arguments, an error message will be printed at the current cursor  position.  Use  refresh	to
       redraw the screen.

NOTES

       After  argument	processing by FMLI, fmlexpr cannot tell the difference between an operator and an operand except by the value. If $a is an
       =, the command:

	 example% fmlexpr $a = =

       looks like:

	 example% fmlexpr = = =

       as the arguments are passed to fmlexpr (and they will all be taken as the = operator). The following works, and returns TRUE:

	 example% fmlexpr X$a = X=

SunOS 5.11							    5 Jul 1990							       fmlexpr(1F)