Basics

PASM has a simple syntax. Each statement stands on its own line. Statements begin with a Parrot instruction code (commonly referred to as an “opcode”). The arguments follow, separated by commas:

[label] opcode 
            dest, source, source ...

If the opcode returns a result, it is stored in the first argument. Sometimes the first register is both a source value and the destination of the operation. The arguments are either registers or constants, though only source arguments can be constants:

LABEL:
    print "The answer is: "
    print 42
    print "\n"
    end                # halt the interpreter

Comments are marked with the hash sign (#) and continue to the end of the line. Any line can start with a label definition like LABEL:, but label definitions can also stand on their own line.

Constants

Integer constants are signed integers.[35]

Integer constants can have a positive (+) or negative (-) sign in front. Binary integers are preceded by 0b or 0B, and hexadecimal integers are preceded by 0x or 0X:

print 42          # integer constant
print -0b101      # binary integer constant with sign
print 0Xdeadbeef  # hex integer constant

Floating-point constants can also be positive or negative. Scientific notation provides an exponent, marked with e or E (the sign of the exponent is optional):

print 3.14159    # floating point constant
print -1.23e+45  # in scientific notation

String constants are wrapped in single or double quotation marks. Quotation marks and other nonprintable characters inside the string have to be escaped by a backslash. ...

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