In Full BASIC, an input reply that ends with a comma excluding any blank characters orders the INPUT statement to assume the line continue to the next line.
Therefore, when the contents of a file is as follows,
"a","b","c", "d","e","f",
an INPUT statement of the form
INPUT #1: a$,b$,c$,d$
processes as the first line continue to the second line since the first line end with a comma, hence it raises an exception of extype 8013 because "e" should be an extra datum.
Using an internal file may make such a file to be read, because Decimal BASIC adopts CSV files as internal files and does not allow line continuation in internal files.
Example.
10 OPEN #1:NAME "A:CSVTEXT.TXT", RECTYPE INTERNAL 20 DO 30 READ #1,IF MISSING THEN EXIT DO: a$,b$,c$,d$ 40 PRINT a$,b$,c$,d$ 50 LOOP 60 CLOSE #1 70 END
Note that current version of Decimal BASIC extends the syntax for an input reply for an INPUT statement as to interpret as a null string is assigned if there are nothing or only blank characters between two commas, but the rule subscribed by Full BASIC standard has priority about the end of a line.
And note that a numeric item cannot be null in an input reply for an INPUT statement.