Search Top Index
HELP LABELS John Gibson March 1986 LABELS in POP-11 are represented by any legal identifier followed by a colon, e.g. loop: l3: +++ : (space is needed if the label consists of 'sign' characters) Labels may be jumped to in GOTO and GO_ON statements, where the label may either be within the same procedure as the jump statement (a local jump), or somewhere within a lexically-enclosing procedure (a non-local jump). A non-local jump to a label is like doing an EXITTO to the target procedure (see HELP *EXITTO), followed by a local jump to the label. Under some circumstances, the use of the syntax label:* (that is, :* instead of :) will produce more efficient code when the label is used in a non-local jump -- see 'Implementation of Non-Local Jumps' in REF *VMCODE. See also HELP *WORDS - for the formation of legal identifiers in POP-11 *GOTO - transferring control within a procedure using a LABEL *GO_ON - jumping to a label according to the value of an integer