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This instruction has a short and long form:
rd LENGTH rd NONT_QUOTED, RHS, POS, LENGTH
The option --dump-asm[=simple] dumps an assembler program with rd
instructions in the short form.
The option --dump-asm=extended dumps an assembler program with rd
instructions in the long form.
The program topdown
uses rd
instructions in the long form.
The instruction consumes LENGTH symbols from a training terminal symbol sequence—increments the current position in the training sequence by LENGTH.
Optionally, the instruction increments the frequency of a production with an auxiliary nonterminal symbol _X_iT
or _X_iTj
at the left-hand side and a consumed terminal symbol sequence at the right-hand side and updates the spur accordingly.
The parameters NONT_QUOTED, RHS, and POS identify this auxiliary nonterminal symbol in the right-hand side of a production of a context-free grammar for a regular expression.
The parameter NONT_QUOTED is a nonterminal symbol specified in double quotation marks and located at the left-hand side of a production that contains the auxiliary nonterminal symbol. The parameter RHS is the index of a right-hand side containing the auxiliary nonterminal symbol. The parameter POS is the position of this auxiliary nonterminal symbol in the right-hand side.
Example:
rd "E", 2, 3, 4
This instruction consumes a sequence of four terminal symbols from a training terminal symbol sequence.
Additionally, the instruction increments the frequency of a production for an auxiliary nonterminal symbol at the left-hand side and the consumed terminal symbol sequence at the right-hand side.
The occurrence of this auxiliary nonterminal symbol is at zero-based position 3 in a right-hand side at zero-based index 2 for the nonterminal symbol E
at the left-hand side.
For example, this auxiliary nonterminal symbol could be the symbol _E_2T4
in the following excerpt of a context-free grammar:
E: A | B | _E_1T C C _E_2T4 D ;
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