## File: expand.w

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 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829 % expand.w % % Copyright 2009-2010 Taco Hoekwater % % This file is part of LuaTeX. % % LuaTeX is free software; you can redistribute it and/or modify it under % the terms of the GNU General Public License as published by the Free % Software Foundation; either version 2 of the License, or (at your % option) any later version. % % LuaTeX is distributed in the hope that it will be useful, but WITHOUT % ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or % FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public % License for more details. % % You should have received a copy of the GNU General Public License along % with LuaTeX; if not, see . @ @c #include "ptexlib.h" @ Only a dozen or so command codes |>max_command| can possibly be returned by |get_next|; in increasing order, they are |undefined_cs|, |expand_after|, |no_expand|, |input|, |if_test|, |fi_or_else|, |cs_name|, |convert|, |the|, |top_bot_mark|, |call|, |long_call|, |outer_call|, |long_outer_call|, and |end_template|.{\emergencystretch=40pt\par} Sometimes, recursive calls to the following |expand| routine may cause exhaustion of the run-time calling stack, resulting in forced execution stops by the operating system. To diminish the chance of this happening, a counter is used to keep track of the recursion depth, in conjunction with a constant called |expand_depth|. Note that this does not catch all possible infinite recursion loops, just the ones that exhaust the application calling stack. The actual maximum value of |expand_depth| is outside of our control, but the initial setting of |100| should be enough to prevent problems. @^system dependencies@> @c static int expand_depth_count = 0; @ The |expand| subroutine is used when |cur_cmd>max_command|. It removes a call'' or a conditional or one of the other special operations just listed. It follows that |expand| might invoke itself recursively. In all cases, |expand| destroys the current token, but it sets things up so that the next |get_next| will deliver the appropriate next token. The value of |cur_tok| need not be known when |expand| is called. Since several of the basic scanning routines communicate via global variables, their values are saved as local variables of |expand| so that recursive calls don't invalidate them. @^recursion@> @c int is_in_csname = 0; @ @c void expand(void) { halfword t; /* token that is being expanded after'' */ halfword p; /* for list manipulation */ halfword cur_ptr; /* for a local token list pointer */ int cv_backup; /* to save the global quantity |cur_val| */ int cvl_backup, radix_backup, co_backup; /* to save |cur_val_level|, etc. */ halfword backup_backup; /* to save |link(backup_head)| */ int save_scanner_status; /* temporary storage of |scanner_status| */ incr(expand_depth_count); if (expand_depth_count >= expand_depth) overflow("expansion depth", (unsigned) expand_depth); cv_backup = cur_val; cvl_backup = cur_val_level; radix_backup = radix; co_backup = cur_order; backup_backup = token_link(backup_head); RESWITCH: if (cur_cmd < call_cmd) { /* Expand a nonmacro */ if (tracing_commands_par > 1) show_cur_cmd_chr(); switch (cur_cmd) { case top_bot_mark_cmd: /* Insert the appropriate mark text into the scanner */ t = cur_chr % marks_code; if (cur_chr >= marks_code) scan_mark_num(); else cur_val = 0; switch (t) { case first_mark_code: cur_ptr = first_mark(cur_val); break; case bot_mark_code: cur_ptr = bot_mark(cur_val); break; case split_first_mark_code: cur_ptr = split_first_mark(cur_val); break; case split_bot_mark_code: cur_ptr = split_bot_mark(cur_val); break; default: cur_ptr = top_mark(cur_val); break; } if (cur_ptr != null) begin_token_list(cur_ptr, mark_text); break; case expand_after_cmd: if (cur_chr == 0) { /* Expand the token after the next token */ /* It takes only a little shuffling to do what \TeX\ calls \.{\\expandafter}. */ get_token(); t = cur_tok; get_token(); if (cur_cmd > max_command_cmd) expand(); else back_input(); cur_tok = t; back_input(); } else { /* \\unless */ /* Negate a boolean conditional and |goto reswitch| */ /* The result of a boolean condition is reversed when the conditional is preceded by \.{\\unless}. */ get_token(); if ((cur_cmd == if_test_cmd) && (cur_chr != if_case_code)) { cur_chr = cur_chr + unless_code; goto RESWITCH; } print_err("You can't use \\unless' before "); print_cmd_chr((quarterword) cur_cmd, cur_chr); print_char('\''); help1("Continue, and I'll forget that it ever happened."); back_error(); } break; case no_expand_cmd: if (cur_chr == 0) { /* Suppress expansion of the next token */ /* The implementation of \.{\\noexpand} is a bit trickier, because it is necessary to insert a special |dont_expand|' marker into \TeX's reading mechanism. This special marker is processed by |get_next|, but it does not slow down the inner loop. Since \.{\\outer} macros might arise here, we must also clear the |scanner_status| temporarily. */ save_scanner_status = scanner_status; scanner_status = normal; get_token(); scanner_status = save_scanner_status; t = cur_tok; back_input(); /* now |start| and |loc| point to the backed-up token |t| */ if (t >= cs_token_flag) { p = get_avail(); set_token_info(p, cs_token_flag + frozen_dont_expand); set_token_link(p, iloc); istart = p; iloc = p; } } else { /* Implement \.{\\primitive} */ /* The \.{\\primitive} handling. If the primitive meaning of the next token is an expandable command, it suffices to replace the current token with the primitive one and restart |expand|. Otherwise, the token we just read has to be pushed back, as well as a token matching the internal form of \.{\\primitive}, that is sneaked in as an alternate form of |ignore_spaces|. An implementation problem surfaces: There really is no |cur_cs| attached to the inserted primitive command, so it is safer to set |cur_cs| to zero. |cur_tok| has a similar problem. And for the non-expanded branch, simply pushing back a token that matches the correct internal command does not work, because that approach would not survive roundtripping to a temporary file or even a token list. In a next version, it would be smart to create |frozen_| versions of all the primitives. Then, this problem would not happen, at the expense of a few hundred extra control sequences. */ save_scanner_status = scanner_status; scanner_status = normal; get_token(); scanner_status = save_scanner_status; cur_cs = prim_lookup(cs_text(cur_cs)); if (cur_cs != undefined_primitive) { t = get_prim_eq_type(cur_cs); if (t > max_command_cmd) { cur_cmd = t; cur_chr = get_prim_equiv(cur_cs); cur_tok = token_val(cur_cmd, cur_chr); cur_cs = 0; goto RESWITCH; } else { back_input(); /* now |loc| and |start| point to a one-item list */ p = get_avail(); set_token_info(p, cs_token_flag + frozen_primitive); set_token_link(p, iloc); iloc = p; istart = p; } } else if (suppress_primitive_error_par == 0) { print_err("Missing primitive name"); help2 ("The control sequence marked does not", "represent any known primitive."); back_error(); } } break; case cs_name_cmd: /* Manufacture a control sequence name; */ if (cur_chr == 0) { manufacture_csname(0); } else if (cur_chr == 1) { inject_last_tested_cs(); } else { manufacture_csname(1); } break; case convert_cmd: conv_toks(); /* this procedure is discussed in Part 27 below */ break; case the_cmd: ins_the_toks(); /* this procedure is discussed in Part 27 below */ break; case combine_toks_cmd: combine_the_toks(cur_chr); break; case if_test_cmd: conditional(); /* this procedure is discussed in Part 28 below */ break; case fi_or_else_cmd: /* Terminate the current conditional and skip to \.{\\fi} */ /* The processing of conditionals is complete except for the following code, which is actually part of |expand|. It comes into play when \.{\\or}, \.{\\else}, or \.{\\fi} is scanned. */ if (tracing_ifs_par > 0) if (tracing_commands_par <= 1) show_cur_cmd_chr(); if (cur_chr > if_limit) { if (if_limit == if_code) { insert_relax(); /* condition not yet evaluated */ } else { print_err("Extra "); print_cmd_chr(fi_or_else_cmd, cur_chr); help1("I'm ignoring this; it doesn't match any \\if."); error(); } } else { while (cur_chr != fi_code) pass_text(); /* skip to \.{\\fi} */ pop_condition_stack(); } break; case input_cmd: /* Initiate or terminate input from a file */ if (cur_chr == 1) force_eof = true; else if (cur_chr == 2) pseudo_start(); else if (cur_chr == 3) { pseudo_start(); iname = 19; } else if (name_in_progress) insert_relax(); else start_input(); break; case variable_cmd: do_variable(); break; case feedback_cmd: do_feedback(); break; default: /* Complain about an undefined macro */ print_err("Undefined control sequence"); help5("The control sequence at the end of the top line", "of your error message was never \\def'ed. If you have", "misspelled it (e.g., \\hobx'), type I' and the correct", "spelling (e.g., I\\hbox'). Otherwise just continue,", "and I'll forget about whatever was undefined."); error(); break; } } else if (cur_cmd < end_template_cmd) { macro_call(); } else { /* Insert a token containing |frozen_endv| */ /* An |end_template| command is effectively changed to an |endv| command by the following code. (The reason for this is discussed below; the |frozen_end_template| at the end of the template has passed the |check_outer_validity| test, so its mission of error detection has been accomplished.) */ cur_tok = cs_token_flag + frozen_endv; back_input(); } cur_val = cv_backup; cur_val_level = cvl_backup; radix = radix_backup; cur_order = co_backup; set_token_link(backup_head, backup_backup); decr(expand_depth_count); } @ @c void complain_missing_csname(void) { print_err("Missing \\endcsname inserted"); help2("The control sequence marked should", "not appear between \\csname and \\endcsname."); back_error(); } @ @c void manufacture_csname(boolean use) { halfword p, q, r; lstring *ss; r = get_avail(); p = r; /* head of the list of characters */ is_in_csname += 1; do { get_x_token(); if (cur_cs == 0) store_new_token(cur_tok); } while (cur_cs == 0); if (cur_cmd != end_cs_name_cmd) { /* Complain about missing \.{\\endcsname} */ complain_missing_csname(); } /* Look up the characters of list |r| in the hash table, and set |cur_cs| */ ss = tokenlist_to_lstring(r, true); is_in_csname -= 1; if (use) { if (ss->l > 0) { cur_cs = string_lookup((char *) ss->s, ss->l); } else { cur_cs = null_cs; } last_cs_name = cur_cs ; free_lstring(ss); flush_list(r); if (cur_cs == null_cs) { /* skip */ } else if (eq_type(cur_cs) == undefined_cs_cmd) { /* skip */ } else { cur_tok = cur_cs + cs_token_flag; back_input(); } } else { if (ss->l > 0) { no_new_control_sequence = false; cur_cs = string_lookup((char *) ss->s, ss->l); no_new_control_sequence = true; } else { cur_cs = null_cs; /* the list is empty */ } last_cs_name = cur_cs ; free_lstring(ss); flush_list(r); if (eq_type(cur_cs) == undefined_cs_cmd) { eq_define(cur_cs, relax_cmd, too_big_char); /* N.B.: The |save_stack| might change */ }; /* the control sequence will now match \.{\\relax}' */ cur_tok = cur_cs + cs_token_flag; back_input(); } } void inject_last_tested_cs(void) { if (last_cs_name != null_cs) { cur_cs = last_cs_name; cur_tok = last_cs_name + cs_token_flag; back_input(); } } @ Sometimes the expansion looks too far ahead, so we want to insert a harmless \.{\\relax} into the user's input. @c void insert_relax(void) { cur_tok = cs_token_flag + cur_cs; back_input(); cur_tok = cs_token_flag + frozen_relax; back_input(); token_type = inserted; } @ Here is a recursive procedure that is \TeX's usual way to get the next token of input. It has been slightly optimized to take account of common cases. @c void get_x_token(void) { /* sets |cur_cmd|, |cur_chr|, |cur_tok|, and expands macros */ RESTART: get_next(); if (cur_cmd <= max_command_cmd) goto DONE; if (cur_cmd >= call_cmd) { if (cur_cmd < end_template_cmd) { macro_call(); } else { cur_cs = frozen_endv; cur_cmd = endv_cmd; goto DONE; /* |cur_chr=null_list| */ } } else { expand(); } goto RESTART; DONE: if (cur_cs == 0) cur_tok = token_val(cur_cmd, cur_chr); else cur_tok = cs_token_flag + cur_cs; } @ The |get_x_token| procedure is equivalent to two consecutive procedure calls: |get_next; x_token|. @c void x_token(void) { /* |get_x_token| without the initial |get_next| */ while (cur_cmd > max_command_cmd) { expand(); get_next(); } if (cur_cs == 0) cur_tok = token_val(cur_cmd, cur_chr); else cur_tok = cs_token_flag + cur_cs; } @ A control sequence that has been \.{\\def}'ed by the user is expanded by \TeX's |macro_call| procedure. Before we get into the details of |macro_call|, however, let's consider the treatment of primitives like \.{\\topmark}, since they are essentially macros without parameters. The token lists for such marks are kept in five global arrays of pointers; we refer to the individual entries of these arrays by symbolic macros |top_mark|, etc. The value of |top_mark(x)|, etc. is either |null| or a pointer to the reference count of a token list. The variable |biggest_used_mark| is an aid to try and keep the code somehwat efficient without too much extra work: it registers the highest mark class ever instantiated by the user, so the loops in |fire_up| and |vsplit| do not have to traverse the full range |0..biggest_mark|. @c halfword top_marks_array[(biggest_mark + 1)]; halfword first_marks_array[(biggest_mark + 1)]; halfword bot_marks_array[(biggest_mark + 1)]; halfword split_first_marks_array[(biggest_mark + 1)]; halfword split_bot_marks_array[(biggest_mark + 1)]; halfword biggest_used_mark; @ @c void initialize_marks(void) { int i; biggest_used_mark = 0; for (i = 0; i <= biggest_mark; i++) { top_mark(i) = null; first_mark(i) = null; bot_mark(i) = null; split_first_mark(i) = null; split_bot_mark(i) = null; } } @ Now let's consider |macro_call| itself, which is invoked when \TeX\ is scanning a control sequence whose |cur_cmd| is either |call|, |long_call|, |outer_call|, or |long_outer_call|. The control sequence definition appears in the token list whose reference count is in location |cur_chr| of |mem|. The global variable |long_state| will be set to |call| or to |long_call|, depending on whether or not the control sequence disallows \.{\\par} in its parameters. The |get_next| routine will set |long_state| to |outer_call| and emit \.{\\par}, if a file ends or if an \.{\\outer} control sequence occurs in the midst of an argument. @c int long_state; /* governs the acceptance of \.{\\par} */ @ The parameters, if any, must be scanned before the macro is expanded. Parameters are token lists without reference counts. They are placed on an auxiliary stack called |pstack| while they are being scanned, since the |param_stack| may be losing entries during the matching process. (Note that |param_stack| can't be gaining entries, since |macro_call| is the only routine that puts anything onto |param_stack|, and it is not recursive.) @c halfword pstack[9]; /* arguments supplied to a macro */ @ After parameter scanning is complete, the parameters are moved to the |param_stack|. Then the macro body is fed to the scanner; in other words, |macro_call| places the defined text of the control sequence at the top of\/ \TeX's input stack, so that |get_next| will proceed to read it next. The global variable |cur_cs| contains the |eqtb| address of the control sequence being expanded, when |macro_call| begins. If this control sequence has not been declared \.{\\long}, i.e., if its command code in the |eq_type| field is not |long_call| or |long_outer_call|, its parameters are not allowed to contain the control sequence \.{\\par}. If an illegal \.{\\par} appears, the macro call is aborted, and the \.{\\par} will be rescanned. @c void macro_call(void) { /* invokes a user-defined control sequence */ halfword r; /* current node in the macro's token list */ halfword p = null; /* current node in parameter token list being built */ halfword q; /* new node being put into the token list */ halfword s; /* backup pointer for parameter matching */ halfword t; /* cycle pointer for backup recovery */ halfword u, v; /* auxiliary pointers for backup recovery */ halfword rbrace_ptr = null; /* one step before the last |right_brace| token */ int n = 0; /* the number of parameters scanned */ halfword unbalance; /* unmatched left braces in current parameter */ halfword m = 0; /* the number of tokens or groups (usually) */ halfword ref_count; /* start of the token list */ int save_scanner_status = scanner_status; /* |scanner_status| upon entry */ halfword save_warning_index = warning_index; /* |warning_index| upon entry */ int match_chr = 0; /* character used in parameter */ warning_index = cur_cs; ref_count = cur_chr; r = token_link(ref_count); if (tracing_macros_par > 0) { /* Show the text of the macro being expanded */ begin_diagnostic(); print_ln(); print_cs(warning_index); token_show(ref_count); end_diagnostic(false); } if (token_info(r) == protected_token) r = token_link(r); if (token_info(r) != end_match_token) { /* Scan the parameters and make |link(r)| point to the macro body; but |return| if an illegal \.{\\par} is detected */ /* At this point, the reader will find it advisable to review the explanation of token list format that was presented earlier, since many aspects of that format are of importance chiefly in the |macro_call| routine. The token list might begin with a string of compulsory tokens before the first |match| or |end_match|. In that case the macro name is supposed to be followed by those tokens; the following program will set |s=null| to represent this restriction. Otherwise |s| will be set to the first token of a string that will delimit the next parameter. */ scanner_status = matching; unbalance = 0; long_state = eq_type(cur_cs); if (long_state >= outer_call_cmd) long_state = long_state - 2; do { set_token_link(temp_token_head, null); if ((token_info(r) >= end_match_token) || (token_info(r) < match_token)) { s = null; } else { match_chr = token_info(r) - match_token; s = token_link(r); r = s; p = temp_token_head; m = 0; } /* Scan a parameter until its delimiter string has been found; or, if |s=null|, simply scan the delimiter string; */ /* If |info(r)| is a |match| or |end_match| command, it cannot be equal to any token found by |get_token|. Therefore an undelimited parameter---i.e., a |match| that is immediately followed by |match| or |end_match|---will always fail the test |cur_tok=info(r)|' in the following algorithm. */ CONTINUE: get_token(); /* set |cur_tok| to the next token of input */ if (cur_tok == token_info(r)) { /* Advance |r|; |goto found| if the parameter delimiter has been fully matched, otherwise |goto continue| */ /* A slightly subtle point arises here: When the parameter delimiter ends with \.{\#\{}', the token list will have a left brace both before and after the |end_match|\kern-.4pt. Only one of these should affect the |align_state|, but both will be scanned, so we must make a correction. */ r = token_link(r); if ((token_info(r) >= match_token) && (token_info(r) <= end_match_token)) { if (cur_tok < left_brace_limit) decr(align_state); goto FOUND; } else { goto CONTINUE; } } /* Contribute the recently matched tokens to the current parameter, and |goto continue| if a partial match is still in effect; but abort if |s=null| */ /* When the following code becomes active, we have matched tokens from |s| to the predecessor of |r|, and we have found that |cur_tok<>info(r)|. An interesting situation now presents itself: If the parameter is to be delimited by a string such as \.{ab}', and if we have scanned \.{aa}', we want to contribute one \.a' to the current parameter and resume looking for a \.b'. The program must account for such partial matches and for others that can be quite complex. But most of the time we have |s=r| and nothing needs to be done. Incidentally, it is possible for \.{\\par} tokens to sneak in to certain parameters of non-\.{\\long} macros. For example, consider a case like \.{\\def\\a\#1\\par!\{...\}}' where the first \.{\\par} is not followed by an exclamation point. In such situations it does not seem appropriate to prohibit the \.{\\par}, so \TeX\ keeps quiet about this bending of the rules. */ if (s != r) { if (s == null) { /* Report an improper use of the macro and abort */ print_err("Use of "); sprint_cs(warning_index); tprint(" doesn't match its definition"); help4 ("If you say, e.g., \\def\\a1{...}', then you must always", "put 1' after \\a', since control sequence names are", "made up of letters only. The macro here has not been", "followed by the required stuff, so I'm ignoring it."); error(); goto EXIT; } else { t = s; do { store_new_token(token_info(t)); incr(m); u = token_link(t); v = s; while (1) { if (u == r) { if (cur_tok != token_info(v)) { goto DONE; } else { r = token_link(v); goto CONTINUE; } } if (token_info(u) != token_info(v)) goto DONE; u = token_link(u); v = token_link(v); } DONE: t = token_link(t); } while (t != r); r = s; /* at this point, no tokens are recently matched */ } } if (cur_tok == par_token) if (long_state != long_call_cmd) if (!suppress_long_error_par) { goto RUNAWAY; } if (cur_tok < right_brace_limit) { if (cur_tok < left_brace_limit) { /* Contribute an entire group to the current parameter */ unbalance = 1; while (1) { fast_store_new_token(cur_tok); get_token(); if (cur_tok == par_token) { if (long_state != long_call_cmd) { if (!suppress_long_error_par) { goto RUNAWAY; } } } if (cur_tok < right_brace_limit) { if (cur_tok < left_brace_limit) { incr(unbalance); } else { decr(unbalance); if (unbalance == 0) break; } } } rbrace_ptr = p; store_new_token(cur_tok); } else { /* Report an extra right brace and |goto continue| */ back_input(); print_err("Argument of "); sprint_cs(warning_index); tprint(" has an extra }"); help6 ("I've run across a }' that doesn't seem to match anything.", "For example, \\def\\a#1{...}' and \\a}' would produce", "this error. If you simply proceed now, the \\par' that", "I've just inserted will cause me to report a runaway", "argument that might be the root of the problem. But if", "your }' was spurious, just type 2' and it will go away."); incr(align_state); long_state = call_cmd; cur_tok = par_token; ins_error(); goto CONTINUE; /* a white lie; the \.{\\par} won't always trigger a runaway */ } } else { /* Store the current token, but |goto continue| if it is a blank space that would become an undelimited parameter */ if (cur_tok == space_token) if (token_info(r) <= end_match_token) if (token_info(r) >= match_token) goto CONTINUE; store_new_token(cur_tok); } incr(m); if (token_info(r) > end_match_token) goto CONTINUE; if (token_info(r) < match_token) goto CONTINUE; FOUND: if (s != null) { /* Tidy up the parameter just scanned, and tuck it away */ /* If the parameter consists of a single group enclosed in braces, we must strip off the enclosing braces. That's why |rbrace_ptr| was introduced. */ if ((m == 1) && (token_info(p) < right_brace_limit) && (p != temp_token_head)) { set_token_link(rbrace_ptr, null); free_avail(p); p = token_link(temp_token_head); pstack[n] = token_link(p); free_avail(p); } else { pstack[n] = token_link(temp_token_head); } incr(n); if (tracing_macros_par > 0) { begin_diagnostic(); print_nl(match_chr); print_int(n); tprint("<-"); show_token_list(pstack[n - 1], null, 1000); end_diagnostic(false); } } /* now |info(r)| is a token whose command code is either |match| or |end_match| */ } while (token_info(r) != end_match_token); } /* Feed the macro body and its parameters to the scanner */ /* Before we put a new token list on the input stack, it is wise to clean off all token lists that have recently been depleted. Then a user macro that ends with a call to itself will not require unbounded stack space. */ while ((istate == token_list) && (iloc == null) && (token_type != v_template)) { /* conserve stack space */ end_token_list(); } begin_token_list(ref_count, macro); iname = warning_index; iloc = token_link(r); if (n > 0) { if (param_ptr + n > max_param_stack) { max_param_stack = param_ptr + n; if (max_param_stack > param_size) overflow("parameter stack size", (unsigned) param_size); } for (m = 0; m <= n - 1; m++) param_stack[param_ptr + m] = pstack[m]; param_ptr = param_ptr + n; } goto EXIT; RUNAWAY: /* Report a runaway argument and abort */ /* If |long_state=outer_call|, a runaway argument has already been reported. */ if (long_state == call_cmd) { runaway(); print_err("Paragraph ended before "); sprint_cs(warning_index); tprint(" was complete"); help3("I suspect you've forgotten a }', causing me to apply this", "control sequence to too much text. How can we recover?", "My plan is to forget the whole thing and hope for the best."); back_error(); } pstack[n] = token_link(temp_token_head); align_state = align_state - unbalance; for (m = 0; m <= n; m++) flush_list(pstack[m]); EXIT: scanner_status = save_scanner_status; warning_index = save_warning_index; }