[fpc-pascal] Labels

[Adriaan van Os]

According to Section 13.0 of the FreePascal Language Reference (version 3.2.0)

	"A label can be an identifier or an integer digit."

What may be meant is that a label can be an identifier or an integer digit-sequence (and that's 
what the compiler accepts)

	label := digit-sequence | identifier .

ISO-7185 and ISO-10206 Pascal both define

	label = digit-sequence .

UCSD-Pascal defines

	label = unsigned-integer ":" .

Turbo Pascal (5.5) defines

	label = digit-sequence .

in the range 0..9999

MetroWerks Pascal (unfortunately) defined a label as

	label = identifier .

The reason for restricting labels to digit-sequences (excluding identifiers) is a parsing problem:

	a :=3;

can also be read as

	a : ......

which is the optional <[ label ":" ]> in the rule for <statement>.

	statement = [ label ":" ] [ simple-statement | structured-statement | asm-statement ] .

This can be solved, of course, but misses the elegance of the ISO-7185/ISO-10206/UCSD/Turbo Pascal 
label definition.

Regards,

Adriaan van Os