Cell references have the form:

 

[integer|string|float|boolean]

cell

{column COL_ID of row ROWNUM

 #OR

  COL_ID, ROWNUM}

of TABLE_NAME

 

For example:

 

cell column Price of row (LastCar+1) of AutoLot cell column Make of row SelectIndex of AutoLot

  in SellCarsDR

cell column 4 of row 4 of DataTable   # These are 

cell 4,4 of DataTable                 # equivalent

float cell column CurCol_SV of row 5 of AutoLot 

 

Because the ESL language allows you to define objects either statically (at compile time) or dynamically (at runtime), you must understand how to use cell references to avoid compile-time and runtime warnings and errors.

 

In the following examples, EmpName is a statically defined column in the table EmpTable; Column_SV and Table_SV are string variables containing the names of a column and a table; and NewColumn and NewTable are constant names that are not defined in the source code, either because of an error or because they are dynamically defined.

 

A column or cell reference can be one of the following:

 

Defined reference, where column and table names are statically created; for example:

 

copy (cell column EmpName of row 1 of EmpTable)

 to EmployeeName

 

ESL generates a warning if you specify in a cell reference the name of a table that is not defined (if you use the -warn switch when compiling).

 

Variable reference, which uses ESL variables for the column and/or table name; for example:

 

copy (integer cell column Column_SV of row 1

    of Table_SV) to CurrentValue

 

(See Explicit Data Types for an explanation of why this example requires that you include the data type integer.) ESL generates a compile-time warning for any column/table reference in which the table identifier is a variable and the column identifier is not, and no column with that identifier exists in any table (if you use the -warn switch when compiling).

 

Undefined reference (neither of the above two types), where the column or table name is not defined at compile-time, either due to an error or a forward reference; for example:

 

copy (string cell column NewColumn row 1

  of NewTable) to StringValue

 

ESL generates a compile-time warning for any column/table reference that contains an undefined column or table name at compile-time (if you use the -warn switch when compiling). ESL generates a runtime error for any column/table reference that contains an undefined column and/or table identifier at runtime.

 

In addition, note the following concerning cell references:

 

You can use a cell reference in the same places as expressions of that cell's data type.

You can use a cell reference as the destination for a copy statement, but not for an append or extract statement.