SP Expression Functions

 FIELDLENX()    Returns length of field
 EXPBLOCK()     Returns a codeblock to evaluate an expresson
 FIELDTYPEX()   Returns type of field
 FIELDPOSX()    Returns position of field named in expression
 FIELDDECX()    Returns decimals of field
 PARSFIELD()    Exracts the name of the field from an expression
 BLANKREC()     Blanks out a record
 PARSALIAS()    Exracts the name of the alias from an expression
 WORKBLOCK()    Returns a set-get block for field named in an expression
 BLANKFIELD()   Returns a blank value corresponding to a field
 ISBLANKREC()   Determines if a record is blank
 ISFIELD()      Determines if an expression is the name of a field
 ISTHISAREA()   Determines if expression is the name of a field in this area

SP_ISTHISAREA

ISTHISAREA()

  Short:
  ------
  ISTHISAREA() Determines if expression is the name of a field
  in this area

  Returns:
  --------
  <lIsThisArea> => Is the expression a field in this
  area

  Syntax:
  -------
  ISTHISAREA(cExpress)

  Description:
  ------------
  Determines if <cExpress> contains the name of a field
  in this area.

  If <cExpress> contains an alias, the area of the
  alias will be checked.

  ISTHISAREA() first calls ISFIELD() to ensure the
  expression is a field name.

  If a field in another area is passed, and no alias is
  used, False will be returned.

  Examples:
  ---------
   ISTHISAREA("LASTNAME")             // actual field,  returns .t.

   ISTHISAREA("CUSTOMER->LASTNAME")  // actual field, returns .t.

   ISTHISAREA("LEFT(LNAME,5)")        // expression, returns  .f.

   ISTHISAREA("AGENT")                //field, but in another area. Returns .f.

  Notes:
  -------
  Companion functions are ISFIELD(), ISEDITABLE(),
  PARSFIELD(), PARSALIAS(), EXPBLOCK(), WORKBLOCK()

  Source:
  -------
  S_FIELDS.PRG

 

SP_ISFIELD

ISFIELD()

  Short:
  ------
  ISFIELD() Determines if an expression is the name of a field

  Returns:
  --------
  <lIsfield> => Is the expression a field

  Syntax:
  -------
  ISFIELD(cExpress)

  Description:
  ------------
  Determines if <cExpress> contains the name of a
  field. If <cExpress> contains an alias, the area of the alias
  will be checked.

  Examples:
  ---------
   isfield( "LASTNAME" )            // actual field, returns  .t.

   isfield( "CUSTOMER->LASTNAME")   // actual field, returns  .t.

   isfield( "LEFT(LNAME,5)" )       // expression, returns .f.

  Notes:
  -------
  Companion functions are ISTHISAREA(), ISEDITABLE(),
  PARSFIELD(), PARSALIAS(), EXPBLOCK(), WORKBLOCK()

  Source:
  -------
  S_FIELDS.PRG

 

SP_EXPBLOCK

EXPBLOCK()

  Short:
  ------
  EXPBLOCK() Returns a codeblock to evaluate an expresson

  Returns:
  --------
  <bBlock> => codeblock to evaluate an expression

  Syntax:
  -------
  EXPBLOCK(cExpress)

  Description:
  ------------
  Returns a codeblock built around the expression in
  cExpress.

  Using EVAL() on the codeblock will return the current
  value of the expression.

  Examples:
  ---------
   cExp := "UPPER(LEFT(CUSTOMER->LNAME,5))"
   bExp := EXPBLOCK(cExp)

   ?eval(bExp)
     // displays current value of customer->lname, upper,left 5

  Notes:
  -------
  See also WORKBLOCK()

  Source:
  -------
  S_FIELDS.PRG