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paren.c

/*
 *      paren.c             logo parenthesizing module            dko
 *
 *    Copyright (C) 1993 by the Regents of the University of California
 *
 *      This program 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.
 *  
 *      This program 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 General Public License for more details.
 *  
 *      You should have received a copy of the GNU General Public License
 *      along with this program; if not, write to the Free Software
 *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#define WANT_EVAL_REGS 1
#include "logo.h"
#include "globals.h"
#include <ctype.h>

NODE *the_generation;

/* Set the line pointer for a tree.
 */ 
void make_line(NODE *tree, NODE *line) {
    setobject(tree, line);
    settype(tree, LINE);
}

void untreeify(NODE *node) {
    settreepair__tree(node, NIL);
    settype(node, CONS);
}

void untreeify_line(NODE *line) {
    if (line != NIL && is_list(line)) {
      untreeify_line(car(line));
      untreeify_line(cdr(line));
      untreeify(line);
    }
}

void untreeify_body(NODE *body) {
    NODE *body_ptr;

    for (body_ptr = body; body_ptr != NIL; body_ptr = cdr(body_ptr)) {
      untreeify_line(car(body_ptr));
    }
    untreeify(body);
}

void untreeify_proc(NODE *tproc) {
    untreeify_body(bodylist__procnode(tproc));
}

/* Treeify a body by appending the trees of the lines.
 */ 
void make_tree_from_body(NODE *body) {

    NODE *body_ptr, *end_ptr = NIL, *tree = NIL;

    if (body == NIL ||
      (is_tree(body) && generation__tree(body) == the_generation))
          return;
    if (is_tree(body)) untreeify_body(body);
    for (body_ptr = body; body_ptr != NIL; body_ptr = cdr(body_ptr)) {
      tree = car(body_ptr);
      if (tree == NIL) continue;  /* skip blank line */
      this_line = tree;
      make_tree(tree);
      if (is_tree(tree)) {
          tree = tree__tree(tree);
          make_line(tree, car(body_ptr));
          if (end_ptr == NIL)
            settree__tree(body, tree);
          else
            setcdr(end_ptr, tree);
          if (generation__tree(car(body_ptr)) == UNBOUND)
            setgeneration__tree(body, UNBOUND);
/*        untreeify(car(body_ptr)); */
          while (cdr(tree) != NIL)
            tree = cdr(tree);
          end_ptr = tree;
      } else {    /* error while treeifying */
          untreeify(body);
          return;
      }
    }
    settype(body, TREE);
}

NODE *tree_dk_how;

/* Treeify a list of tokens (runparsed or not).
 */ 
void make_tree(NODE *list) {

    NODE *tree = NIL;
    NODE *paren_line(NODE *);

    if (list == NIL ||
      (is_tree(list) && generation__tree(list) == the_generation))
          return;
    if (!runparsed(list)) make_runparse(list);
    tree_dk_how = NIL;
    tree = paren_line(parsed__runparse(list));
    if (tree != NIL && tree != UNBOUND) {
      settype(list, TREE);
      settree__tree(list, tree);
      if (tree_dk_how != NIL || stopping_flag==THROWING)
          setgeneration__tree(list, UNBOUND);
    }
}

NODE *gather_args(NODE *, NODE *, NODE **, BOOLEAN, NODE **);
NODE *paren_infix(NODE *, NODE **, int, BOOLEAN);
NODE *gather_some_args(int, int, NODE **, BOOLEAN, NODE **);

/* Fully parenthesize a complete line, i.e. transform it from a flat list
 * to a tree.
 */ 
NODE *paren_line(NODE *line) {

    NODE *retval = NIL;
    NODE *paren_expr(NODE **expr, BOOLEAN inparen);
    NODE *paren_infix(NODE *left, NODE **rest, int old_pri, BOOLEAN inparen);

    if (line == NIL) return line;
    retval = paren_expr(&line, FALSE);
    if (NOT_THROWING && retval != UNBOUND) {
      retval = paren_infix(retval, &line, -1, FALSE);
      retval = cons(retval, paren_line(line));
    }
    return retval;
}

/* See if an unknown procedure name starts with SET */
int is_setter(NODE *name) {
    NODE *string = cnv_node_to_strnode(name);

    if (getstrlen(string) < 4) return FALSE;
    return !low_strncmp(getstrptr(string), "set", 3);
}

/* Check for FD100, give warning, insert space */

NODE *missing_alphabetic, *missing_numeric;

int missing_space(NODE *name) {
    NODE *str = strnode__caseobj(name);
    char *s = getstrptr(str);
    FIXNUM len = getstrlen(str);
    char *t;
    char ch;
    char alpha[100], numer[100];
    int i;
    NODE *first;

    t = s+len-1;
    ch = *t;
    if (!isdigit(ch)) return 0;
    i = 1;
    while ((t>s) && (isdigit(*--t))) i++;
    if (t<=s) return 0;
    strncpy(numer,t+1,i);
    numer[i] = '\0';
    strncpy(alpha,s,len-i);
    alpha[len-i] = '\0';
    first = intern(make_strnode(alpha, 0, len-i, STRING, strnzcpy));
    if (procnode__caseobj(first) == UNDEFINED && NOT_THROWING)
      silent_load(first, NULL);    /* try ./<first>.lg */
    if (procnode__caseobj(first) == UNDEFINED && NOT_THROWING)
      silent_load(first, logolib); /* try <logolib>/<first> */
    if (procnode__caseobj(first) == UNDEFINED) return 0;
    missing_alphabetic = first;
    missing_numeric = make_intnode(atoi(numer));
    err_logo(MISSING_SPACE,
           cons_list(0, cons_list(0, missing_alphabetic, missing_numeric,
                            END_OF_LIST),
                      name, END_OF_LIST));
    return 1;
}

/* Parenthesize an expression.  Set expr to the node after the first full
 * expression.
 */ 
NODE *paren_expr(NODE **expr, BOOLEAN inparen) {

    NODE *first = NIL, *tree = NIL, *pproc, *retval;
    NODE **ifnode = (NODE **)NIL;

    if (*expr == NIL) {
      if (inparen) err_logo(PAREN_MISMATCH, NIL);
      return *expr;
    }
    first = car(*expr);
    pop(*expr);
    if (nodetype(first) == CASEOBJ && !numberp(first)) {
      if (first == Left_Paren) {
          tree = paren_expr(expr, TRUE);
          tree = paren_infix(tree, expr, -1, TRUE);
          if (*expr == NIL)
            err_logo(PAREN_MISMATCH, NIL);
          else if (car(*expr) != Right_Paren) {
            int parens;

            tree_dk_how=UNBOUND;   /* throw the rest away */
            for (parens = 0; *expr; pop(*expr)) {
                if (car(*expr) == Left_Paren)
                  parens++;
                else if (car(*expr) == Right_Paren)
                  if (parens-- == 0) {
                      pop(*expr);
                      break;
                  }
            }
            first = car(tree);
            tree = cons(Not_Enough_Node, NIL);  /* tell eval */
            err_logo(TOO_MUCH, first);
          }
          else
            pop(*expr);
          retval = tree;
      } else if (first == Right_Paren) {
          err_logo(UNEXPECTED_PAREN, NIL);
          if (inparen) push(first, *expr);
          retval = NIL;
      } else if (first == Minus_Sign) {
          push(Minus_Tight, *expr);
          retval = paren_infix(make_intnode((FIXNUM) 0), expr, -1, inparen);
      } else {    /* it must be a procedure */
          if (procnode__caseobj(first) == UNDEFINED && NOT_THROWING &&
            first != Null_Word)
                silent_load(first, NULL);    /* try ./<first>.lg */
          if (procnode__caseobj(first) == UNDEFINED && NOT_THROWING &&
            first != Null_Word)
                silent_load(first, logolib); /* try <logolib>/<first> */
          pproc = procnode__caseobj(first);
          if (pproc == UNDEFINED) {
            if (missing_space(first)) {
                push(missing_numeric, *expr);
                first = missing_alphabetic;
                pproc = procnode__caseobj(first);
                retval = gather_args(first, pproc, expr, inparen, ifnode);
                if (retval != UNBOUND) {
                  retval = cons(first, retval);
                }
            } else if (is_setter(first)) {
                retval = gather_some_args(0, 1, expr, inparen, ifnode);
                if (retval != UNBOUND) {
                  retval = cons(first, retval);
                }
            } else {
                retval = cons(first, NIL);
                tree_dk_how = first;
            }
          } else if (nodetype(pproc) == INFIX && NOT_THROWING) {
            err_logo(NOT_ENOUGH, first);
            retval = cons(first, NIL);
          } else {
            /* Kludge follows to turn IF to IFELSE sometimes. */
            if (isName(first, Name_if)) {
                ifnode = &first;
            }
            retval = gather_args(first, pproc, expr, inparen, ifnode);
            if (retval != UNBOUND) {
                retval = cons(first, retval);
            }
          }
      }
    } else if (is_list(first)) {   /* quoted list */
      retval = make_quote(first);
    } else {
      return first;
    }
    return retval;
}

/* Gather the correct number of arguments to proc into a list.  Set args to
 * immediately after the last arg.
 */ 
NODE *gather_args(NODE *newfun, NODE *pproc, NODE **args, BOOLEAN inparen,
              NODE **ifnode) {
    int min, max;
    NODE /* *oldfun, */ *result;
    
    if (nodetype(pproc) == CONS) {
      min = (inparen ? getint(minargs__procnode(pproc))
                   : getint(dfltargs__procnode(pproc)));
      max = (inparen ? getint(maxargs__procnode(pproc))
                   : getint(dfltargs__procnode(pproc)));
    } else { /* primitive */
      min = (inparen ? getprimmin(pproc) : getprimdflt(pproc));
      if (min < 0) {        /* special form */
          result = *args;
          *args = NIL;
          return result;
/*
          oldfun = fun;
          fun = newfun;
          result = (*getprimfun(pproc))(*args);
          fun = oldfun;
          return result;
 */
      }
    /* Kludge follows to allow EDIT and CO without input without paren */ 
      if (getprimmin(pproc) == OK_NO_ARG) min = 0;
      max = (inparen ? getprimmax(pproc) : getprimdflt(pproc));
    }
    return gather_some_args(min, max, args, inparen, ifnode);
}

/* Make a list of the next n expressions, where n is between min and max.
 * Set args to immediately after the last expression.
 */ 
NODE *gather_some_args(int min, int max, NODE **args, BOOLEAN inparen,
                   NODE **ifnode) {
    NODE *paren_infix(NODE *left, NODE **rest, int old_pri, BOOLEAN inparen);

    if (*args == NIL || car(*args) == Right_Paren ||
          (nodetype(car(*args)) == CASEOBJ &&
           nodetype(procnode__caseobj(car(*args))) == INFIX)) {
      if (min > 0) return cons(Not_Enough_Node, NIL);
    } else if (max == 0) {
      if (ifnode != (NODE **)NIL && is_list(car(*args))) {
          /* if -> ifelse kludge */
          NODE *retval;
          err_logo(IF_WARNING, NIL);
          *ifnode = theName(Name_ifelse);
          retval = paren_expr(args, FALSE);
          retval = paren_infix(retval, args, -1, inparen);
          return cons(retval, gather_some_args(min, max, args,
                                     inparen, (NODE **)NIL));
      }
    } else {
      if (max < 0) max = 0;   /* negative max means unlimited */
      if (car(*args) != Right_Paren &&
            (nodetype(car(*args)) != CASEOBJ ||
             nodetype(procnode__caseobj(car(*args))) != INFIX)) {
          NODE *retval = paren_expr(args, FALSE);
          retval = paren_infix(retval, args, -1, inparen);
          return cons(retval, gather_some_args(min - 1, max - 1, args,
                                     inparen, ifnode));
      }
    }
    return NIL;
}

/* Calculate the priority of a procedure.
 */ 
int priority(NODE *proc_obj) {

    NODE *pproc;

    if (proc_obj == Minus_Tight) return PREFIX_PRIORITY+4;
    if (nodetype(proc_obj) != CASEOBJ ||
      (pproc = procnode__caseobj(proc_obj)) == UNDEFINED ||
      nodetype(pproc) != INFIX)
          return 0;
    return getprimpri(pproc);
}

/* Parenthesize an infix expression.  left_arg is the expression on the left
 * (already parenthesized), and rest is a pointer to the list starting with the
 * infix procedure, if it's there.  Set rest to after the right end of the
 * infix expression.
 */ 
NODE *paren_infix(NODE *left_arg, NODE **rest, int old_pri, BOOLEAN inparen) {

    NODE *infix_proc, *retval;
    int pri;

    if (*rest == NIL || !(pri = priority(infix_proc = car(*rest)))
                 || pri <= old_pri) 
      return left_arg;
    pop(*rest);
    retval = paren_expr(rest, inparen);
    retval = paren_infix(retval, rest, pri, inparen);
    retval = cons_list(0,infix_proc, left_arg, retval, END_OF_LIST);
    return paren_infix(retval, rest, old_pri, inparen);
}

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