How to read a comma separated file that has a line who has a comma at the end.

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.


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