# Language Extensions: Source Forms

The following are extensions to the methods and rules for source forms:

- Tab-formatting as a method to code lines

- The letter D as a debugging statement indicator in column 1 of fixed or tab source form

- An optional statement field width of 132 columns for fixed or tab source form

- An optional sequence number field for fixed source form

- Up to 511 continuation lines in a source program

Parent topic: Summary of Language Extensions