Expressions Reference

Chapter Updated 2/12/99




Expression Operands

OperandTypeFunction
+AlphaConcatonate
+NumericAddition
-AlphaConcatonate, remove white space
-NumericSubtraction
*NumericMultiplication
/NumericDivision
**NumericExponentiation
<LogicalLess Than
>LogicalGreater Than
=LogicalEqual
<>LogicalNot Equal
#LogicalNot Equal
<=LogicalLess Than or Equal
>=LogicalGreater Than or Equal
$LogicalContains
->N/AIdentifies database field ie; DATABASE->FIELD



Expression Functions

Expression FunctionXbase C++ MethodDescription
ABS()xbDouble EXPN::ABS( xbDouble d ) Returns absolute numeric value of argument.
ASC()xbLong EXPN::ASC( char * String ) Returns ASCII code of left character of string.
AT()xbLong EXPN::AT( char *s1, char *s2 ) Returns starting position of first alphanumeric argument in second argument.
CDOW()char * EXPN::CDOW( char Date8 ) Returns name of the day of the week of Date8.
CHR()char * EXPN::CHR( xbLong l ) Returns ASCII character corresponding to numeric value supplied.
CMONTH()char * EXPN::CMONTH( char * Date8 ) Returns name of the month of Date8.
DATE()char * EXPN::DATE() Returns system date.
DAY()xbLong EXPN::DAY( char * Date8 ) Returns numeric value of the day of the month for Date8.
DESCEND()EXPN::DESCEND()Descend
DTOC()char * EXPN::DTOC( char * Date8 ) Returns a date converted to format MM/DD/YY.
EXP()xbDouble EXPN::EXP( xbDouble d ) Returns exponential for supplied value.
INT()xbLong EXPN::INT( xbDouble d ) Converts any numeric value to an integer.
ISALPHA()xbLong EXPN::ISALPHA( char * String ) Returns TRUE if string is alpha.
ISLOWER()xbLong EXPN::ISLOWER( char * String ) Returns TRUE if string is lower case.
ISUPPER()xbLong EXPN::ISUPPER( char * String ) Returns TRUE if string is upper case.
LEFT()char * EXPN::LEFT( char * String, xbShort Len ) Returns Len characters from the left side of String.
LEN()xbLong EXPN::LEN( char * String ) eturns the number of characters in the String.
LOG()xbDouble EXPN::LOG( xbDouble d ) Returns the natural log of d.
LOWER()char * EXPN::LOWER( char * String ) Converts a string to lower case.
LTRIM()char * EXPN::LTRIM( char * String ) Eliminates leading white space from String.
MAX()xbDouble EXPN::MAX( xbDouble d1, xbDouble d2 ) Returns the larger of two numeric arguments.
MIN()xbDouble EXPN::MIN(xbDouble d1, xbDouble d2 ) Returns the smaller of two numeric arguments.
MONTH()xbLong EXPN::MONTH( char * Date8 ) Returns numeric month for Date8.
REPLICATE()char * EXPN::REPLICATE( char * String, xbShort Count ) Replicates String Conut times.
RIGHT()char * EXPN::RIGHT( char * String, xbShort Count ) Returns Count characters from the right side of String.
RTRIM()char * EXPN::RTRIM( char * String ) Removes trailing white space from String.
SPACE()char * EXPN::SPACE( xbShort Count ) Returns a buffer filled with Count spaces.
SQRT()xbDouble EXPN::SQRT( xbDouble d ) Returns square root of d.
STR()char * EXPN::STR( xbDouble d ) Converts a number to a string.
SUBSTR()char * EXPN::SUBSTR( char * String, xbShort StartPos, xbShort Len ) Returns a string form String starting at position StartPos for a length of Len.
TRIM()char * EXPN::TRIM( char * String ) Same as RTRIM.
UPPER()char * EXPN::UPPER( char * String ) Converts a string to upper case.
VAL()xbLong EXPN::VAL( char * String ) Converts a string to an integer.
YEAR()xbLong EXPN::YEAR( char * Date8 ) Returns numeric year from Date8.



Expression Processing Method List

MethodDescription
GetCharResult()Get char * result from processed expression
GetDoubResult()Get xbDouble result from processed expression
GetIntResult()Get a xbLong result from processed expression
GetExpressionHandle()Get an expression's handle
GetExpressionResultType(xbExpression *)Get expression result type
ParseExpression(char *,xbDbf *)Parse an expression
ProcessExpression(xbExpression *)Process a parsed expression


Method Definitions


Method char * xbXBase::GetCharResult()


This method returns a char * result from a processed expression.

See the program listing in chapter 5 for an example of how to use this method.

Method xbDouble xbXBase::GetDoubleResult()


This method returns a xbDouble result from a processed expression.

See the program listing in chapter 5 for an example of how to use this method.

Method xbLong xbXBase::GetIntResult()


This method returns a xbLong result from a processed expression.

See the program listing in chapter 5 for an example of how to use this method.

Method xbExpression * xbXBase::GetExpressionHandle()


This method returns a handle to a recently parsed expression.

See the program listing in chapter 5 for an example of how to use this method.

Method char xbXBase::GetExpressionResultType( xbExpression * e )


This method returns the result type for a given expression e.

Method Return Codes

Return Code ValueDescription
Cchar * result from processed expression
NxbDouble result from processed expression
LxbLong (also logical) result from processed expression


See the program listing in chapter 5 for an example of how to use this method.

Method xbShort ParseExpression( char * exp, DBF * d)


This method parses expression exp.
d is a pointer to a database used for resolving any fieldname which does not contain the -> operator.

See the program listing in chapter 5 for an example of how to use this method.

Method xbShort ProcessExpression( xbExpression * e )


This method processes parsed expression e.

See the program listing in chapter 5 for an example of how to use this method.


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