RosettaCodeData/Task/Execute-HQ9+/ALGOL-68/execute-hq9+.alg
2023-07-01 13:44:08 -04:00

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# the increment-only accumulator #
INT hq9accumulator := 0;
# interpret a HQ9+ code string #
PROC hq9 = ( STRING code )VOID:
FOR i TO UPB code
DO
CHAR op = code[ i ];
IF op = "Q" OR op = "q"
THEN
# display the program #
print( ( code, newline ) )
ELIF op = "H" OR op = "h"
THEN
print( ( "Hello, world!", newline ) )
ELIF op = "9"
THEN
# 99 bottles of beer #
FOR bottles FROM 99 BY -1 TO 1 DO
STRING bottle count = whole( bottles, 0 ) + IF bottles > 1 THEN " bottles" ELSE " bottle" FI;
print( ( bottle count, " of beer on the wall", newline ) );
print( ( bottle count, " bottles of beer.", newline ) );
print( ( "Take one down, pass it around,", newline ) );
IF bottles > 1
THEN
print( ( whole( bottles - 1, 0 ), " bottles of beer on the wall.", newline, newline ) )
FI
OD;
print( ( "No more bottles of beer on the wall.", newline ) )
ELIF op = "+"
THEN
# increment the accumulator #
hq9accumulator +:= 1
ELSE
# unimplemented operation #
print( ( """", op, """ not implemented", newline ) )
FI
OD;
# test the interpreter #
BEGIN
STRING code;
print( ( "HQ9+> " ) );
read( ( code, newline ) );
hq9( code )
END