/* walk -- walk through a tree, evaluating nodes */
extern List *walk(Tree *tree0, Binding *binding0, int flags) {
Tree *volatile tree = tree0;
Binding *volatile binding = binding0;
SIGCHK();
top:
if (tree == NULL)
return true;
switch (tree->kind) {
case nConcat: case nList: case nQword: case nVar: case nVarsub:
case nWord: case nThunk: case nLambda: case nCall: case nPrim: {
List *list;
Ref(Binding *, bp, binding);
list = glom(tree, binding, TRUE);
binding = bp;
RefEnd(bp);
return eval(list, binding, flags);
}
case nAssign:
return assign(tree->u[0].p, tree->u[1].p, binding);
case nLet: case nClosure:
Ref(Tree *, body, tree->u[1].p);
binding = letbindings(tree->u[0].p, binding, binding, flags);
tree = body;
RefEnd(body);
goto top;
case nLocal:
return local(tree->u[0].p, tree->u[1].p, binding, flags);
case nFor:
return forloop(tree->u[0].p, tree->u[1].p, binding, flags);
case nMatch:
return matchpattern(tree->u[0].p, tree->u[1].p, binding);
case nExtract:
return extractpattern(tree->u[0].p, tree->u[1].p, binding);
default:
panic("walk: bad node kind %d", tree->kind);
}
NOTREACHED;
}
/* glob -- globbing prepass (glob if we need to, and dispatch for tilde expansion) */
extern List *glob(List *list, StrList *quote) {
List *lp;
StrList *qp;
Boolean doglobbing = FALSE;
for (lp = list, qp = quote; lp != NULL; lp = lp->next, qp = qp->next)
if (qp->str != QUOTED) {
assert(lp->term != NULL);
assert(!isclosure(lp->term));
Ref(char *, str, getstr(lp->term));
assert(qp->str == UNQUOTED || strlen(qp->str) == strlen(str));
if (hastilde(str, qp->str)) {
Ref(List *, l0, list);
Ref(List *, lr, lp);
Ref(StrList *, q0, quote);
Ref(StrList *, qr, qp);
str = expandhome(str, qp);
lr->term = mkstr(str);
lp = lr;
qp = qr;
list = l0;
quote = q0;
RefEnd4(qr, q0, lr, l0);
}
if (haswild(str, qp->str))
doglobbing = TRUE;
RefEnd(str);
}
/* assign -- bind a list of values to a list of variables */
static List *assign(Tree *varform, Tree *valueform0, Binding *binding0) {
Ref(List *, result, NULL);
Ref(Tree *, valueform, valueform0);
Ref(Binding *, binding, binding0);
Ref(List *, vars, glom(varform, binding, FALSE));
if (vars == NULL)
fail("es:assign", "null variable name");
Ref(List *, values, glom(valueform, binding, TRUE));
result = values;
for (; vars != NULL; vars = vars->next) {
List *value;
Ref(char *, name, getstr(vars->term));
if (values == NULL)
value = NULL;
else if (vars->next == NULL || values->next == NULL) {
value = values;
values = NULL;
} else {
value = mklist(values->term, NULL);
values = values->next;
}
vardef(name, binding, value);
RefEnd(name);
}
RefEnd4(values, vars, binding, valueform);
RefReturn(result);
}
extern Term *mkstr(char *str) {
Term *term;
Ref(char *, string, str);
term = gcnew(Term);
term->str = string;
term->closure = NULL;
RefEnd(string);
return term;
}
extern List *fsplit(const char *sep, List *list, Boolean coalesce) {
Ref(List *, lp, list);
startsplit(sep, coalesce);
for (; lp != NULL; lp = lp->next) {
char *s = getstr(lp->term);
splitstring(s, strlen(s), TRUE);
}
RefEnd(lp);
return endsplit();
}
static Var *mkvar(List *defn) {
Ref(Var *, var, NULL);
Ref(List *, lp, defn);
var = gcnew(Var);
var->env = NULL;
var->defn = lp;
var->flags = hasbindings(lp) ? var_hasbindings : 0;
RefEnd(lp);
RefReturn(var);
}
/* sortlist */
extern List *sortlist(List *list) {
if (length(list) > 1) {
Vector *v = vectorize(list);
sortvector(v);
gcdisable(0);
Ref(List *, lp, listify(v->count, v->vector));
gcenable();
list = lp;
RefEnd(lp);
}
static List *callsettor(char *name, List *defn) {
Push p;
List *settor;
if (specialvar(name) || (settor = varlookup2("set-", name, NULL)) == NULL)
return defn;
Ref(List *, lp, defn);
Ref(List *, fn, settor);
varpush(&p, "0", mklist(mkstr(name), NULL));
lp = listcopy(eval(append(fn, lp), NULL, 0));
varpop(&p);
RefEnd(fn);
RefReturn(lp);
}
static noreturn failexec(char *file, List *args) {
List *fn;
assert(gcisblocked());
fn = varlookup("fn-%exec-failure", NULL);
if (fn != NULL) {
int olderror = errno;
Ref(List *, list, append(fn, mklist(mkstr(file), args)));
RefAdd(file);
gcenable();
RefRemove(file);
eval(list, NULL, 0);
RefEnd(list);
errno = olderror;
}
eprint("%s: %s\n", file, esstrerror(errno));
exit(1);
}
extern char *getstr(Term *term) {
char *s = term->str;
Closure *closure = term->closure;
assert((s == NULL) != (closure == NULL));
if (s != NULL)
return s;
#if 0 /* TODO: decide whether getstr() leaves term in closure or string form */
Ref(Term *, tp, term);
s = str("%C", closure);
tp->str = s;
tp->closure = NULL;
RefEnd(tp);
return s;
#else
return str("%C", closure);
#endif
}
/* letbindings -- create a new Binding containing let-bound variables */
static Binding *letbindings(Tree *defn0, Binding *outer0,
Binding *context0, int evalflags) {
Ref(Binding *, binding, outer0);
Ref(Binding *, context, context0);
Ref(Tree *, defn, defn0);
for (; defn != NULL; defn = defn->u[1].p) {
assert(defn->kind == nList);
if (defn->u[0].p == NULL)
continue;
Ref(Tree *, assign, defn->u[0].p);
assert(assign->kind == nAssign);
Ref(List *, vars, glom(assign->u[0].p, context, FALSE));
Ref(List *, values, glom(assign->u[1].p, context, TRUE));
if (vars == NULL)
fail("es:let", "null variable name");
for (; vars != NULL; vars = vars->next) {
List *value;
Ref(char *, name, getstr(vars->term));
if (values == NULL)
value = NULL;
else if (vars->next == NULL || values->next == NULL) {
value = values;
values = NULL;
} else {
value = mklist(values->term, NULL);
values = values->next;
}
binding = mkbinding(name, value, binding);
RefEnd(name);
}
RefEnd3(values, vars, assign);
}
RefEnd2(defn, context);
RefReturn(binding);
}
/* expandhome -- do tilde expansion by calling fn %home */
static char *expandhome(char *s, StrList *qp) {
int c;
size_t slash;
List *fn = varlookup("fn-%home", NULL);
assert(*s == '~');
assert(qp->str == UNQUOTED || *qp->str == 'r');
if (fn == NULL)
return s;
for (slash = 1; (c = s[slash]) != '/' && c != '\0'; slash++)
;
Ref(char *, string, s);
Ref(StrList *, quote, qp);
Ref(List *, list, NULL);
RefAdd(fn);
if (slash > 1)
list = mklist(mkstr(gcndup(s + 1, slash - 1)), NULL);
RefRemove(fn);
list = eval(append(fn, list), NULL, 0);
if (list != NULL) {
if (list->next != NULL)
fail("es:expandhome", "%%home returned more than one value");
Ref(char *, home, getstr(list->term));
if (c == '\0') {
string = home;
quote->str = QUOTED;
} else {
char *q;
size_t pathlen = strlen(string);
size_t homelen = strlen(home);
size_t len = pathlen - slash + homelen;
s = gcalloc(len + 1, &StringTag);
memcpy(s, home, homelen);
memcpy(&s[homelen], &string[slash], pathlen - slash);
s[len] = '\0';
string = s;
q = quote->str;
if (q == UNQUOTED) {
q = gcalloc(len + 1, &StringTag);
memset(q, 'q', homelen);
memset(&q[homelen], 'r', pathlen - slash);
q[len] = '\0';
} else if (strchr(q, 'r') == NULL)
q = QUOTED;
else {
q = gcalloc(len + 1, &StringTag);
memset(q, 'q', homelen);
memcpy(&q[homelen], "e->str[slash], pathlen - slash);
q[len] = '\0';
}
quote->str = q;
}
RefEnd(home);
}
RefEnd2(list, quote);
RefReturn(string);
}
/* eval -- evaluate a list, producing a list */
extern List *eval(List *list0, Binding *binding0, int flags) {
Closure *volatile cp;
List *fn;
if (++evaldepth >= maxevaldepth)
fail("es:eval", "max-eval-depth exceeded");
Ref(List *, list, list0);
Ref(Binding *, binding, binding0);
Ref(char *, funcname, NULL);
restart:
if (list == NULL) {
RefPop3(funcname, binding, list);
--evaldepth;
return true;
}
assert(list->term != NULL);
if ((cp = getclosure(list->term)) != NULL) {
switch (cp->tree->kind) {
case nPrim:
assert(cp->binding == NULL);
list = prim(cp->tree->u[0].s, list->next, binding, flags);
break;
case nThunk:
list = walk(cp->tree->u[0].p, cp->binding, flags);
break;
case nLambda:
ExceptionHandler
Push p;
Ref(Tree *, tree, cp->tree);
Ref(Binding *, context,
bindargs(tree->u[0].p,
list->next,
cp->binding));
if (funcname != NULL)
varpush(&p, "0",
mklist(mkterm(funcname,
NULL),
NULL));
list = walk(tree->u[1].p, context, flags);
if (funcname != NULL)
varpop(&p);
RefEnd2(context, tree);
CatchException (e)
if (termeq(e->term, "return")) {
list = e->next;
goto done;
}
throw(e);
EndExceptionHandler
break;
case nList: {
list = glom(cp->tree, cp->binding, TRUE);
list = append(list, list->next);
goto restart;
}
default:
panic("eval: bad closure node kind %d",
cp->tree->kind);
}
goto done;
}
/* the logic here is duplicated in $&whatis */
Ref(char *, name, getstr(list->term));
fn = varlookup2("fn-", name, binding);
if (fn != NULL) {
funcname = name;
list = append(fn, list->next);
RefPop(name);
goto restart;
}
if (isabsolute(name)) {
char *error = checkexecutable(name);
if (error != NULL)
fail("$&whatis", "%s: %s", name, error);
list = forkexec(name, list, flags & eval_inchild);
RefPop(name);
goto done;
}
RefEnd(name);
fn = pathsearch(list->term);
if (fn != NULL && fn->next == NULL
&& (cp = getclosure(fn->term)) == NULL) {
char *name = getstr(fn->term);
list = forkexec(name, list, flags & eval_inchild);
goto done;
}
list = append(fn, list->next);
goto restart;
done:
--evaldepth;
if ((flags & eval_exitonfalse) && !istrue(list))
exit(exitstatus(list));
RefEnd2(funcname, binding);
RefReturn(list);
}
/* forloop -- evaluate a for loop */
static List *forloop(Tree *defn0, Tree *body0,
Binding *binding, int evalflags) {
static List MULTIPLE = { NULL, NULL };
Ref(List *, result, true);
Ref(Binding *, outer, binding);
Ref(Binding *, looping, NULL);
Ref(Tree *, body, body0);
Ref(Tree *, defn, defn0);
for (; defn != NULL; defn = defn->u[1].p) {
assert(defn->kind == nList);
if (defn->u[0].p == NULL)
continue;
Ref(Tree *, assign, defn->u[0].p);
assert(assign->kind == nAssign);
Ref(List *, vars, glom(assign->u[0].p, outer, FALSE));
Ref(List *, list, glom(assign->u[1].p, outer, TRUE));
if (vars == NULL)
fail("es:for", "null variable name");
for (; vars != NULL; vars = vars->next) {
char *var = getstr(vars->term);
looping = mkbinding(var, list, looping);
list = &MULTIPLE;
}
RefEnd3(list, vars, assign);
SIGCHK();
}
looping = reversebindings(looping);
RefEnd(defn);
ExceptionHandler
for (;;) {
Boolean allnull = TRUE;
Ref(Binding *, bp, outer);
Ref(Binding *, lp, looping);
Ref(Binding *, sequence, NULL);
for (; lp != NULL; lp = lp->next) {
Ref(List *, value, NULL);
if (lp->defn != &MULTIPLE)
sequence = lp;
assert(sequence != NULL);
if (sequence->defn != NULL) {
value = mklist(sequence->defn->term,
NULL);
sequence->defn = sequence->defn->next;
allnull = FALSE;
}
bp = mkbinding(lp->name, value, bp);
RefEnd(value);
}
RefEnd2(sequence, lp);
if (allnull) {
RefPop(bp);
break;
}
result = walk(body, bp, evalflags & eval_exitonfalse);
RefEnd(bp);
SIGCHK();
}
CatchException (e)
if (!termeq(e->term, "break"))
throw(e);
result = e->next;
EndExceptionHandler
RefEnd3(body, looping, outer);
RefReturn(result);
}