list.cpp

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/************************************************************************
 ************************************************************************
    FAUST compiler
    Copyright (C) 2003-2004 GRAME, Centre National de Creation Musicale
    ---------------------------------------------------------------------
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    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
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 ************************************************************************
 ************************************************************************/
 
 
 
/*****************************************************************************
******************************************************************************
                                LIST 
                        Y. Orlarey, (c) Grame 2002
------------------------------------------------------------------------------
This file contains several extensions to the tree library : 
    - lists : based on a operations like cons, hd , tl, ... 
    - environments : list of associations (key value)
    - property list : used to annotate trees


 API:
 ---- 

    List :
    -----
    
    nil                 = predefined empty list
    cons (x,l)          = create a nex list of head x and tail l
    hd(cons(x,l))       = x, 
    tl (cons(x,l))      = l
    nth(l,i)            = ith element of l (or nil)
    replace(l,i,e)      = a copy of l where the ith element is e
    len(l)              = number of elements of l
    isNil(nil)          = true      (false otherwise)
    isList(cons(x,l))   = true      (false otherwise)
    list(a,b,..)        = cons(a, list(b,...))
    
    lmap(f, cons(x,l))  = cons(f(x), lmap(f,l))
    reverse([a,b,..,z]) = [z,..,b,a]
    reverseall([a,b,..,z])  = [ra(z),..,ra(b),ra(a)] where ra is reverseall
    
    Set :
    -----
    (Sets are implemented as ordered lists of elements without duplication)
    
    isElement(e,s)          = true if e is an element of set s, false otherwise
    addElement(e,s)         = s U {e}
    remElement(e,s)         = s - {e}
    singleton(e)            = {e}
    list2set(l)             = convert a list into a set 
    setUnion(s1,s2)         = s1 U s2
    setIntersection(s1,s2)  = s1 intersection s2
    setDifference(s1,s2)    = s1 - s2
    
    Environment : 
    -------------
    
    An 'environment' is a stack of pairs (key x value) used to keep track of lexical bindings
    
    pushEnv (key, val, env) -> env' create a new environment
    searchEnv (key,&v,env) -> bool  search for key in env and set v accordingly
    
    search(k1,&v, push(k2,x,env))   = true and v is set to x if k1==k2
                                    = search(k1,&v,env) if k1 != k2
    Property list :
    ---------------
    
    Every tree can be annotated with an 'attribut' field. This attribute field 
    can be used to manage a property list (pl). A property list is a list of pairs
    key x value, with three basic operations :
    
    setProperty (t, key, val) -> t      add the association (key x val) to the pl of t
    getProperty (t, key, &val) -> bool  search the pp of t for the value associated to key
    remProperty (t, key) -> t           remove any association (key x ?) from the pl of t
    
 Warning :
 ---------
 Since reference counters are used for garbage collecting, one must be careful not to 
 create cycles in trees. The only possible source of cycles is by setting the attribut
 of a tree t to a tree t' that contains t as a subtree.  
    
 History :
 ---------
    2002-02-08 : First version
    2002-02-20 : New description of the API, non recursive lmap and reverse
    2002-03-29 : Added function remElement(e,set), corrected comment error
    
******************************************************************************
*****************************************************************************/

#include <stdlib.h>
#include "list.hh"
#include "compatibility.hh"
#include <map>
#include <cstdlib>

// predefined symbols CONS and NIL
Sym CONS = symbol("cons");
Sym NIL  = symbol("nil");

// predefined nil tree
Tree nil = tree(NIL);


//------------------------------------------------------------------------------
// Printing of trees with special case for lists
//------------------------------------------------------------------------------

static bool printlist (Tree l, FILE* out)
{
    if (isList(l)) {
        
        char sep = '(';
        
        do {
            fputc(sep, out); sep = ',';
            print(hd(l));
            l = tl(l);
        } while (isList(l));
        
        if (! isNil(l)) {
            fprintf(out, " . ");
            print(l, out);
        }
        
        fputc(')', out);
        return true;
        
    } else if (isNil(l)) {
        
        fprintf(out, "nil");
        return true;
        
    } else {
        
        return false;
    }
}

void print (Tree t, FILE* out)
{
    int i; double f; Sym s; void* p;
    
    if (printlist(t, out))      return;
    
    Node n = t->node();
         if (isInt(n, &i))      fprintf (out, "%d", i);
    else if (isDouble(n, &f))   fprintf (out, "%f", f);
    else if (isSym(n, &s))      fprintf (out, "%s", name(s));
    else if (isPointer(n, &p))  fprintf (out, "#%p", p);
    
    int k = t->arity();
    if (k > 0) {
        char sep = '[';
        for (int i=0; i<k; i++) {
            fputc(sep, out); sep = ',';
            print(t->branch(i), out);
        }
        fputc(']', out);
    } 
}


//------------------------------------------------------------------------------
// Elements of list
//------------------------------------------------------------------------------

Tree nth (Tree l, int i)
{
    while (isList(l)) {
        if (i == 0)  return hd(l);
        l = tl(l);
        i--;
    }
    return nil;
}

Tree replace(Tree l, int i, Tree e)
{
    return (i==0) ? cons(e,tl(l)) : cons( hd(l), replace(tl(l),i-1,e) );
}


int len (Tree l)
{
    int     n = 0;
    while (isList(l)) { l = tl(l); n++; }
    return n;
}


//------------------------------------------------------------------------------
// Mapping and reversing
//------------------------------------------------------------------------------

Tree rconcat (Tree l, Tree q)
{
    while (isList(l)) { q = cons(hd(l),q); l = tl(l); }
    return q;
}

Tree concat (Tree l, Tree q)
{
    return rconcat(reverse(l), q);
}

Tree lrange (Tree l, int i, int j)
{
    Tree    r = nil;
    int     c = j;
    while (c>i) r = cons( nth(l,--c), r);
    return r;
}

//------------------------------------------------------------------------------
// Mapping and reversing
//------------------------------------------------------------------------------

static Tree rmap (tfun f, Tree l)
{
    Tree r = nil;
    while (isList(l)) { r = cons(f(hd(l)),r); l = tl(l); }
    return r;
}

Tree reverse (Tree l)
{
    Tree r = nil;
    while (isList(l)) { r = cons(hd(l),r); l = tl(l); }
    return r;
}

Tree lmap (tfun f, Tree l)
{
    return reverse(rmap(f,l));
}

Tree reverseall (Tree l)
{
    return isList(l) ? rmap(reverseall, l) : l;
}


//------------------------------------------------------------------------------
// Sets : implemented as ordered list
//------------------------------------------------------------------------------

bool isElement (Tree e, Tree l)
{
    while (isList(l)) {
        if (hd(l) == e) return true;
        if (hd(l) > e) return false;
        l = tl(l);
    }
    return false;
}

Tree addElement(Tree e, Tree l)
{
    if (isList(l)) {
        if (e < hd(l)) {
            return cons(e,l);
        } else if (e == hd(l)) {
            return l;
        } else {
            return cons(hd(l), addElement(e,tl(l)));
        }
    } else {
        return cons(e,nil);
    }
}

Tree remElement(Tree e, Tree l)
{
    if (isList(l)) {
        if (e < hd(l)) {
            return l;
        } else if (e == hd(l)) {
            return tl(l);
        } else {
            return cons(hd(l), remElement(e,tl(l)));
        }
    } else {
        return nil;
    }
}

Tree singleton (Tree e)
{
    return list1(e);
}

Tree list2set (Tree l)
{
    Tree s = nil;
    while (isList(l)) {
        s = addElement(hd(l),s);
        l = tl(l);
    }
    return s;
}

Tree setUnion (Tree A, Tree B)
{
    if (isNil(A))       return B;
    if (isNil(B))       return A;
    
    if (hd(A) == hd(B)) return cons(hd(A), setUnion(tl(A),tl(B)));
    if (hd(A) < hd(B))  return cons(hd(A), setUnion(tl(A),B));
    /* hd(A) > hd(B) */ return cons(hd(B), setUnion(A,tl(B)));
}

Tree setIntersection (Tree A, Tree B)
{
    if (isNil(A))       return A;
    if (isNil(B))       return B;
    if (hd(A) == hd(B)) return cons(hd(A), setIntersection(tl(A),tl(B)));
    if (hd(A) < hd(B))  return setIntersection(tl(A),B);
    /* (hd(A) > hd(B)*/ return setIntersection(A,tl(B));
}

Tree setDifference (Tree A, Tree B)
{
    if (isNil(A))       return A;
    if (isNil(B))       return A;
    if (hd(A) == hd(B)) return setDifference(tl(A),tl(B));
    if (hd(A) < hd(B))  return cons(hd(A), setDifference(tl(A),B));
    /* (hd(A) > hd(B)*/ return setDifference(A,tl(B));
}
    
        

//------------------------------------------------------------------------------
// Environments
//------------------------------------------------------------------------------

Tree pushEnv (Tree key, Tree val, Tree env)
{
    return cons (cons(key,val), env);
}

bool searchEnv (Tree key, Tree& v, Tree env)
{
    while (isList(env)) {
        if (hd(hd(env)) == key) {
            v = tl(hd(env));
            return true;
        }
        env = tl(env);
    }
    return false;
}


//------------------------------------------------------------------------------
// Property list
//------------------------------------------------------------------------------

static bool findKey (Tree pl, Tree key, Tree& val)
{
    if (isNil(pl))              return false;
    if (left(hd(pl)) == key)    { val= right(hd(pl)); return true; }
    /*  left(hd(pl)) != key */  return findKey (tl(pl), key, val); 
}

static Tree updateKey (Tree pl, Tree key, Tree val)
{
    if (isNil(pl))              return cons ( cons(key,val), nil );
    if (left(hd(pl)) == key)    return cons ( cons(key,val), tl(pl) );
    /*  left(hd(pl)) != key */  return cons ( hd(pl), updateKey( tl(pl), key, val ));
}

static Tree removeKey (Tree pl, Tree key)
{
    if (isNil(pl))              return nil;
    if (left(hd(pl)) == key)    return tl(pl);
    /*  left(hd(pl)) != key */  return cons (hd(pl), removeKey(tl(pl), key));
}


#if 0
void setProperty (Tree t, Tree key, Tree val)
{
    CTree* pl = t->attribut();
    if (pl) t->attribut(updateKey(pl, key, val)); 
    else    t->attribut(updateKey(nil, key, val));
}

void remProperty (Tree t, Tree key)
{
    CTree* pl = t->attribut();
    if (pl) t->attribut(removeKey(pl, key));
}

bool getProperty (Tree t, Tree key, Tree& val)
{
    CTree* pl = t->attribut();
    if (pl) return findKey(pl, key, val);
    else    return false;
}

#else
// nouvelle implementation
void setProperty (Tree t, Tree key, Tree val)
{
    t->setProperty(key, val);
}

bool getProperty (Tree t, Tree key, Tree& val)
{
    CTree* pl = t->getProperty(key);
    if (pl) {
        val = pl;
        return true;
    } else {
        return false;
    }
}

void remProperty (Tree t, Tree key)
{
    exit(1); // fonction not implemented
}
#endif


//------------------------------------------------------------------------------
// Bottom Up Tree Mapping
//------------------------------------------------------------------------------

Tree tmap (Tree key, tfun f, Tree t)
{   
    //printf("start tmap\n");
    Tree p; 
    
    if (getProperty(t, key, p)) {
        
        return (isNil(p)) ? t : p;  // truc pour eviter les boucles
        
    } else {

        tvec br;
        int n = t->arity();
        for (int i = 0; i < n; i++) {
            br.push_back( tmap(key, f, t->branch(i)) );
        }

        Tree r1 = tree(t->node(), br);

        Tree r2 = f(r1);
        if (r2 == t) {
            setProperty(t, key, nil);
        } else {
            setProperty(t, key, r2);
        }
        return r2;
    }
}
        




//------------------------------------------------------------------------------
// substitute :remplace toutes les occurences de 'id' par 'val' dans 't'
//------------------------------------------------------------------------------

// genere une clef unique propre � cette substitution
static Tree substkey(Tree t, Tree id, Tree val) 
{
    char    name[256];
    snprintf(name, 255, "SUBST<%p,%p,%p> : ", (CTree*)t, (CTree*)id, (CTree*)val);
    return tree(unique(name));
}   

// realise la substitution proprement dite tout en mettant a jour la propriete
// pour ne pas avoir a la calculer deux fois

static Tree subst (Tree t, Tree propkey, Tree id, Tree val)
{
    Tree p;
    
    if (t==id) {
        return val;
        
    } else if (t->arity() == 0) {
        return t;
    } else if (getProperty(t, propkey, p)) {
        return (isNil(p)) ?  t : p;
    } else {

        tvec br;
        int n = t->arity();
        for (int i = 0; i < n; i++) {
            br.push_back( subst(t->branch(i), propkey, id, val) );
        }

        Tree r = tree(t->node(), br);

        if (r == t) {
            setProperty(t, propkey, nil);
        } else {
            setProperty(t, propkey, r);
        }
        return r;
    }
        
}

// remplace toutes les occurences de 'id' par 'val' dans 't'
Tree substitute (Tree t, Tree id, Tree val)
{
    return subst (t, substkey(t,id,val), id, val);
}