Difference between revisions of "Lianja Operators"

Revision as of 09:24, 5 February 2013

Lianja Operators

Assignment Operators

Values are assigned to memory variables using the the equals = operator.

cVar1 = 'newer value'

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

store 'new value' to cVar1, cVar2

Arithmetic Operators

Lianja 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 Lianja:

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:

Example

cStr1 = [Welcome to Lianja]
? "Lianja" $ cStr1
.T.
 
cStr2 = [Welcome]
// Compares to the end of cStr2
? cStr1 = cStr2
.T.
 
// Compare contents & size
? cStr1 == cStr2
.F.

Logical Operators

Lianja supports the following logical operators:

The logical operators are evaluated from left to right in the following order:

1. Statements enclosed in parentheses
2. NOT,!
3. AND
4. OR, XOR

Example

? .T. and .F. or .T.
.T.

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 Lianja:

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

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, set 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())