Evalue

evalue evaluates a formula contained in a character string.

Syntax

evalue(STRING_EXPR)

• STRING_EXPR is a string expression or a variable that returns the expression to be evaluated.

Examples

# First simple exampleLocal Integer FIELD1FIELD1=evalue("1+1") : # FIELD1 contains now 2# Second example with an array of formulasLocal Char FORMULA(100)(1..3)FORMULA(1)="1+2+3+4"FORMULA(2)="1+10+20"FORMULA(3)="5+4"FIELD1=evalue(FORMULA) : # FIELD1 contains now the result of "1+2+3+41+10+205+4" that gives 266# Third example: check first if the formula is syntactically valid, then manage the error# Returns the result of the evaluation in a string# If an error occurs, ERROR_CODE is not null and the result is an empty stringSubprog EVALUE(FORMULA,RESULT,ERROR_CODE)Value Char FORMULA()Variable Char RESULTVariable Integer ERROR_CODE# Is the formula correct?ERROR_CODE=parse(FORMULA)If ERROR_CODE<>0 : RESULT="" : End : Endif# Handle the errorsOnerrgo ERR_EVALUERESULT=num$(evalue(FORMULA))ERROR_CODE=0End# Error handling$ERR_EVALUERESULT=""ERROR_CODE=errnEnd# Fourth complex example with several evaluations (on meta data)# Dump of the elements in a table (given by [G:abv]adxfname(i))# The file is written in JSONLocal File MYTABLE [MYT]Local Integer I,J,K,L,TLocal Clbfile STRINGVAL(0)Openo filpath("TRA","MYTABLE","dmp"),0 Using [DMP]Wrseq '{ "MYTABLE" : [' Using [DMP]For [MYT]I+=1Wrseq string$(I>1,",")+ '{ "record_number" : '+num$(I)+"," Using [DMP]For J=1 to [G:MYT]nbzon-1 : # We skip the first element (Updtick)Wrseq string$(J>1,","); Using [DMP]# evaluate the dimension of the fieldK=evalue("dim([F:MYT]"+[G:MYT]adxfname(J)+")")# evaluate the type of the fieldT=evalue("type([F:MYT]"+[G:MYT]adxfname(J)+")")Wrseq '"'+[G:MYT]adxfname(J)+'" : ' Using [DMP]If K>1 : Wrseq '[' Using [DMP] : EndifFor L=0 To K-1Wrseq string$(L>0,","); Using [DMP] : # Separator between the members of a collection If find(T,1,2,4,5,6,7,8) : # Type that can be transformed by num$# evaluate the value of the columnWrseq num$(evalue("[F:MYT]"+[G:MYT]adxfname(J)+"("+num$(L)+")")) Using [DMP]Elsif find(T,522,523,524)Wrseq '"(Object)"' Using [DMP]Elsif T=3# evaluate the value of the column (date type)Wrseq '"'+format$("D:4Y[-]MM[-]DD",evalue("[F:MYT]"+[G:MYT]adxfname(J)+"("+num$(L)+")"))+'"' Using [DMP]Else# evaluate the value of the column (string or datetime)# In strings, the double quotes are replaced by spaces in order to avoid incorrect stringsSTRINGVAL=num$(evalue("[F:MYT]"+[G:MYT]adxfname(J)+"("+num$(L)+")"))Wrseq '"'+ctrans(STRINGVAL,'"',' ')+'"' Using [DMP]EndifNext LIf K>1 : Wrseq ']' Using [DMP] : EndifNext JWrseq "}" using [DMP]NextWrseq "]}" using [DMP]Openo Using [DMP]

Description

evalue evaluates the content of a character string as a formula and returns the result of the evaluation.

If the argument of evalue is a string array, the different lines in the array are concatenated and the result is evaluated.

Comment

A second argument can be given for evalue, but this syntax is deprecated and must not be used.

Associated errors

evalue contains a formula that is evaluated, and any error raised by the functions in the formula can occur. There is also the following error list:

See also

parse.