Difference between revisions of "Recital Operators"

Revision as of 14:11, 6 November 2009

Recital Operators

Assignment Operators

Values are assigned to memory variables using the the equals = operator or the inline assignment := operator.

cVAR1 = 'newer value'
cVAR1 := 'newest value'

Note that the store command can also be used to assign valuesand can operate on more than one memory variable in a single command.

store 'new value' to cVAR1, cVAR2

Arithmetic Operators

Recital supports the use of the following Arithmetic Operators:

When dealing with Date data types, the operators work as follows:

Example

? 2*3^2
        18
? 2*25%7
      1.00
? date() + 30 - date()
        30

Comparison Operators

The following Comparison Operators are supported in Recital:

The Comparison Operators are always evaluated from left to right.

The following ’wildcard’ characters can be used for == pattern matching:

In SQL statements, the following wildcard characters are available:

Note: For FoxPro compatibility reasons, wildcard pattern matching is not available when SET COMPATIBLE is set to FOXPRO/FOXBASE/FOXPLUS/VFP.

Example

cSTR1 = [Welcome to Recital]
? "Recital" $ cSTR1
.T.
 
cSTR2 = [Welcome]
// Compares to the end of cSTR2
? cSTR1 = cSTR2
.T.
 
// Compare contents & size
? cSTR1 == cSTR2
.F.

Increment and Decrement Operators

The ++ operator is used to automatically increment a previously declared numeric memory variable by one. The ++ operator must be placed at the beginning of the command line.

Example

i=0
do while i <100
    ++ i
enddo

The -- operator is used to automatically decrement a previously declared numeric memory variable by one. The -- operator must be placed at the beginning of the command line.

Example

i=100
do while i > 0
    --i
enddo

String Concatenation Operator

When dealing with string data types, the + and - operators perform the following concatenation operations:

Example

? [Hello] + [ ] + [ World]
Hello World
? [Hello     ] - [ World]
Hello World

String Search Operators

The following String Search Operators are supported in Recital:

String Substitution Operator

&<memvar> | (<exp>)

The & String Substitution or Macro Operator substitutes the contents of the specified <memvar> or evaluated expression, (<exp>), into the command line. To use a macro in the middle of a word, it is necessary to end the variable name with a '.'. Any type of memory variable can be substituted as a macro; expressions must be enclosed in round brackets.

Example

subscript = 10
i10i = 5
? i&subscript.i
         5

Execution Operator

The ! Execution Operator provides the facility for running operating system commands or external programs from within the system. The !! operator works in the same way, but any output is displayed at the current screen location rather than the top of the screen.

Example

! ps -ef
!! ps -ef

Concatenation of Strings and Other Data Types

If SET STRICT is OFF, non-string expressions are automatically converted as they are added to a string. If SET STRICT is ON, expressions must be converted manually using the ETOS() or other data conversion functions. By default, STRICT is ON.

Example

set strict off
echo "This string can add numerics and dates etc. " + 100.89 + " " + date()
 
set strict on
echo "This string can add numerics and dates etc. " + str(100.89,6,2) + " " + etos(date())

Summary