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FWEB version 1.62 (September 25, 1998)
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Based on version 0.5 of S. Levy's CWEB [copyright (C) 1987 Princeton University]
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@x-----------------------------------------------------------------------------
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@* STACKS for OUTPUT. The output process uses a stack to keep track
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of what is going on at different ``levels'' as the modules are being
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written out. Entries on this stack have a number of parts:
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\yskip\hang |end_field| is the |tok_mem| location where the replacement
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text of a particular level will end;
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\hang |byte_field| is the |tok_mem| location from which the next token
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on a particular level will be read;
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\hang |name_field| points to the name corresponding to a particular level;
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\hang |repl_field| points to the replacement text currently being read
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at a particular level.
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\hang |mod_field| is the module number, or zero if this is a macro.
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\hang |global_Language| is the overriding language for the module and its
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\hang |Language| is the current language for the module. It will differ
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from |global_Language| if a language command was encountered in the middle
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\hang |macro_buf| is the current scratch space for the macro processor;
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|macro_buf_end| is its end.
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\yskip\noindent The current values of these nine quantities are referred
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to quite frequently, so they are stored in a separate place (|cur_state|)
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instead of in the |stack| array. We call the current values |cur_end|,
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|cur_byte|, |cur_name|, |cur_repl|, |cur_mod|, |cur_global_language|, and
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The global variable |stack_ptr| tells how many levels of output are
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currently in progress. The end of all output occurs when the stack is
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empty, i.e., when |stack_ptr=stack|.
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eight_bits HUGE *end_field; // Ending location of replacement text.
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eight_bits HUGE *byte_field; // Present location within replacement text.
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name_pointer name_field; // |byte_start| index for text being output.
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text_pointer repl_field; // |tok_start| index for text being output.
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sixteen_bits mod_field; // Module number, or zero if not a module.
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PARAMS global_params,params; // Various flags.
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eight_bits HUGE *macro_buf, HUGE *mp, HUGE *macro_buf_end;
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// Current macro buffer.
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typedef output_state HUGE *stack_pointer;
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@ Here are the synonyms for the current values of the stack.
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@d cur_end cur_state.end_field // Current ending location in |tok_mem|.
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@d cur_byte cur_state.byte_field // Location of next output byte in |tok_mem|.
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@d cur_name cur_state.name_field // Pointer to current name being expanded.
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@d cur_repl cur_state.repl_field // Pointer to current replacement text.
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@d cur_mod cur_state.mod_field // Current module number being expanded.
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@d cur_language cur_state.language // Current language.
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@d cur_global_language cur_state.global_params.Language
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// Global language for this level.
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@d cur_params cur_state.params // Local flags.
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@d cur_global_params cur_state.global_params // Global flags.
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/* Current macro buffer params. */
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@d macrobuf cur_state.macro_buf
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@d cur_mp cur_state.mp
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@d macrobuf_end cur_state.macro_buf_end
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EXTERN output_state cur_state; /* |cur_end|, |cur_byte|, |cur_name|,
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|cur_repl|, |cur_mod|, |cur_global_language|, and |cur_language|. */
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EXTERN long stck_size; // Number of simultaneous levels of macro expansion.
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EXTERN output_state HUGE *stack; // Dynamic array: Info for non-current levels.
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EXTERN stack_pointer stck_end; // End of |stack|.
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EXTERN stack_pointer stck_ptr; // First unused loc.\ in the output state stack.
added
removed
Web/stacks.hweb
