ast.c

/*
  AST
  interface to front-end, obtains and translates syntax trees
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <assert.h>
#include <sys/types.h>
#include <limits.h>
#include <errno.h>
#include <math.h>
#include <setjmp.h>
#include "julia.h"

#include "flisp.h"

static char flisp_system_image[] = {
#include "julia_flisp.boot.inc"
};

extern fltype_t *iostreamtype;

static jl_value_t *scm_to_julia(value_t e);
static value_t julia_to_scm(jl_value_t *v);

DLLEXPORT void jl_lisp_prompt(void)
{
    fl_applyn(1, symbol_value(symbol("__start")), fl_cons(FL_NIL,FL_NIL));
}

value_t fl_defined_julia_global(value_t *args, uint32_t nargs)
{
    argcount("defined-julia-global", nargs, 1);
    (void)tosymbol(args[0], "defined-julia-global");
    char *name = symbol_name(args[0]);
    return jl_boundp(jl_current_module, jl_symbol(name)) ? FL_T : FL_F;
}

value_t fl_invoke_julia_macro(value_t *args, uint32_t nargs)
{
    if (nargs < 1)
        argcount("invoke-julia-macro", nargs, 1);
    (void)tosymbol(args[0], "invoke-julia-macro");
    jl_sym_t *name = jl_symbol(symbol_name(args[0]));
    jl_function_t *f = jl_get_expander(jl_current_module, name);
    if (f == NULL)
        return FL_F;
    jl_value_t **margs;
    int na = nargs-1;
    if (na > 0)
        margs = alloca(na * sizeof(jl_value_t*));
    else
        margs = NULL;
    int i;
    for(i=0; i < na; i++) margs[i] = NULL;
    JL_GC_PUSHARGS(margs, na);
    for(i=0; i < na; i++) margs[i] = scm_to_julia(args[i+1]);
    jl_value_t *result;

    JL_TRY {
        result = jl_apply(f, margs, na);
    }
    JL_CATCH {
        JL_GC_POP();
        jl_show(jl_exception_in_transit);
        ios_putc('\n', jl_current_output_stream());
        return fl_cons(symbol("error"), FL_NIL);
    }
    // protect result from GC, otherwise it could be freed during future
    // macro expansions, since it will be referenced only from scheme and
    // not julia.
    // all calls to invoke-julia-macro happen under a single call to jl_expand,
    // so the preserved value stack is popped there.
    jl_gc_preserve(result);
    value_t scm = julia_to_scm(result);
    JL_GC_POP();
    return scm;
}

static builtinspec_t julia_flisp_ast_ext[] = {
    { "defined-julia-global", fl_defined_julia_global },
    { "invoke-julia-macro", fl_invoke_julia_macro },
    { NULL, NULL }
};

static fltype_t *jvtype;

void jl_init_frontend(void)
{
    fl_init(2*512*1024);
    value_t img = cvalue(iostreamtype, sizeof(ios_t));
    ios_t *pi = value2c(ios_t*, img);
    ios_static_buffer(pi, flisp_system_image, sizeof(flisp_system_image));
    
    if (fl_load_system_image(img)) {
        ios_printf(ios_stderr, "fatal error loading system image\n");
        exit(1);
    }

    fl_applyn(0, symbol_value(symbol("__init_globals")));

    jvtype = define_opaque_type(symbol("julia_value"), sizeof(void*),
                                NULL, NULL);

    assign_global_builtins(julia_flisp_ast_ext);
}

static jl_sym_t *scmsym_to_julia(value_t s)
{
    assert(issymbol(s));
    if (fl_isgensym(s)) {
        static char gsname[16];
        char *n = uint2str(&gsname[1], sizeof(gsname)-1,
                           ((gensym_t*)ptr(s))->id, 10);
        *(--n) = '#';
        return jl_symbol(n);
    }
    return jl_symbol(symbol_name(s));
}

static jl_value_t *scm_to_julia_(value_t e);

static jl_value_t *full_list(value_t e)
{
    size_t ln = llength(e);
    if (ln == 0) return jl_an_empty_cell;
    jl_array_t *ar = jl_alloc_cell_1d(ln);
    size_t i=0;
    while (iscons(e)) {
        jl_cellset(ar, i, scm_to_julia_(car_(e)));
        e = cdr_(e);
        i++;
    }
    return (jl_value_t*)ar;
}

static jl_value_t *full_list_of_lists(value_t e)
{
    size_t ln = llength(e);
    if (ln == 0) return jl_an_empty_cell;
    jl_array_t *ar = jl_alloc_cell_1d(ln);
    size_t i=0;
    while (iscons(e)) {
        jl_cellset(ar, i, full_list(car_(e)));
        e = cdr_(e);
        i++;
    }
    return (jl_value_t*)ar;
}

static jl_value_t *scm_to_julia(value_t e)
{
#ifdef JL_GC_MARKSWEEP
    int en = jl_gc_is_enabled();
    jl_gc_disable();
#endif
    jl_value_t *v = scm_to_julia_(e);
#ifdef JL_GC_MARKSWEEP
    if (en) jl_gc_enable();
#endif
    return v;
}

static jl_value_t *scm_to_julia_(value_t e)
{
    if (fl_isnumber(e)) {
        if (iscprim(e)) {
            numerictype_t nt = cp_numtype((cprim_t*)ptr(e));
            switch (nt) {
            case T_DOUBLE:
                return (jl_value_t*)jl_box_float64(*(double*)cp_data((cprim_t*)ptr(e)));
            case T_INT64:
                return (jl_value_t*)jl_box_int64(*(int64_t*)cp_data((cprim_t*)ptr(e)));
            case T_UINT8:
                return (jl_value_t*)jl_box_uint8(*(uint8_t*)cp_data((cprim_t*)ptr(e)));
            case T_UINT16:
                return (jl_value_t*)jl_box_uint16(*(uint16_t*)cp_data((cprim_t*)ptr(e)));
            case T_UINT32:
                return (jl_value_t*)jl_box_uint32(*(uint32_t*)cp_data((cprim_t*)ptr(e)));
            case T_UINT64:
                return (jl_value_t*)jl_box_uint64(*(uint64_t*)cp_data((cprim_t*)ptr(e)));
            default:
                ;
            }
        }
        if (isfixnum(e)) {
            int64_t ne = numval(e);
#ifdef __LP64__
            return (jl_value_t*)jl_box_int64(ne);
#else
            if (ne > S32_MAX || ne < S32_MIN)
                return (jl_value_t*)jl_box_int64(ne);
            return (jl_value_t*)jl_box_int32((int32_t)ne);
#endif
        }
        uint64_t n = toulong(e, "scm_to_julia");
#ifdef __LP64__
        return (jl_value_t*)jl_box_int64((int64_t)n);
#else
        if (n > S32_MAX)
            return (jl_value_t*)jl_box_int64((int64_t)n);
        return (jl_value_t*)jl_box_int32((int32_t)n);
#endif
    }
    if (issymbol(e)) {
        if (!fl_isgensym(e)) {
            char *sn = symbol_name(e);
            if (!strcmp(sn, "true"))
                return jl_true;
            else if (!strcmp(sn, "false"))
                return jl_false;
        }
        return (jl_value_t*)scmsym_to_julia(e);
    }
    if (fl_isstring(e)) {
        return jl_pchar_to_string(cvalue_data(e), cvalue_len(e));
    }
    if (e == FL_F) {
        return jl_false;
    }
    if (e == FL_T) {
        return jl_true;
    }
    if (e == FL_NIL) {
        return (jl_value_t*)jl_null;
    }
    if (iscons(e)) {
        value_t hd = car_(e);
        if (issymbol(hd)) {
            jl_sym_t *sym = scmsym_to_julia(hd);
            /* tree node types:
               goto  gotoifnot  label  return
               lambda  call  =  quote
               null  top  isbound  method
               body  file new
               line  enter  leave
            */
            size_t n = llength(e)-1;
            size_t i;
            if (sym == lambda_sym) {
                jl_expr_t *ex = jl_exprn(lambda_sym, n);
                e = cdr_(e);
                value_t largs = car_(e);
                jl_cellset(ex->args, 0, full_list(largs));
                e = cdr_(e);
                
                value_t ee = car_(e);
                jl_array_t *vinf = jl_alloc_cell_1d(3);
                jl_cellset(vinf, 0, full_list(car_(ee)));
                ee = cdr_(ee);
                jl_cellset(vinf, 1, full_list_of_lists(car_(ee)));
                ee = cdr_(ee);
                jl_cellset(vinf, 2, full_list_of_lists(car_(ee)));
                assert(!iscons(cdr_(ee)));
                jl_cellset(ex->args, 1, vinf);
                e = cdr_(e);
                
                for(i=2; i < n; i++) {
                    assert(iscons(e));
                    jl_cellset(ex->args, i, scm_to_julia_(car_(e)));
                    e = cdr_(e);
                }
                return
                    (jl_value_t*)jl_new_lambda_info((jl_value_t*)ex, jl_null);
            }

            e = cdr_(e);
            if (sym == line_sym && n==1) {
                return jl_new_struct(jl_linenumbernode_type,
                                     scm_to_julia_(car_(e)));
            }
            if (sym == label_sym) {
                return jl_new_struct(jl_labelnode_type,
                                     scm_to_julia_(car_(e)));
            }
            if (sym == goto_sym) {
                return jl_new_struct(jl_gotonode_type,
                                     scm_to_julia_(car_(e)));
            }
            if (sym == quote_sym) {
                return jl_new_struct(jl_quotenode_type,
                                     scm_to_julia_(car_(e)));
            }
            if (sym == top_sym) {
                return jl_new_struct(jl_topnode_type,
                                     scm_to_julia_(car_(e)));
            }
            jl_expr_t *ex = jl_exprn(sym, n);
            for(i=0; i < n; i++) {
                assert(iscons(e));
                jl_cellset(ex->args, i, scm_to_julia_(car_(e)));
                e = cdr_(e);
            }
            return (jl_value_t*)ex;
        }
        else {
            jl_error("malformed tree");
        }
    }
    if (iscprim(e) && cp_class((cprim_t*)ptr(e))==wchartype) {
        jl_value_t *wc =
            jl_box32(jl_char_type, *(int32_t*)cp_data((cprim_t*)ptr(e)));
        return wc;
    }
    if (iscvalue(e) && cv_class((cvalue_t*)ptr(e)) == jvtype) {
        return *(jl_value_t**)cv_data((cvalue_t*)ptr(e));
    }
    jl_error("malformed tree");
    
    return (jl_value_t*)jl_null;
}

static value_t array_to_list(jl_array_t *a)
{
    long i;
    value_t lst=FL_NIL, temp=FL_NIL;
    fl_gc_handle(&lst);
    fl_gc_handle(&temp);
    for(i=a->length-1; i >= 0; i--) {
        temp = julia_to_scm(jl_cellref(a,i));
        lst = fl_cons(temp, lst);
    }
    fl_free_gc_handles(2);
    return lst;
}

static value_t julia_to_scm(jl_value_t *v)
{
    if (jl_is_symbol(v)) {
        return symbol(((jl_sym_t*)v)->name);
    }
    if (v == jl_true) {
        return FL_T;
    }
    if (v == jl_false) {
        return FL_F;
    }
    if (jl_is_expr(v)) {
        jl_expr_t *ex = (jl_expr_t*)v;
        value_t args = array_to_list(ex->args);
        fl_gc_handle(&args);
        value_t hd = julia_to_scm((jl_value_t*)ex->head);
        value_t scmv = fl_cons(hd, args);
        fl_free_gc_handles(1);
        return scmv;
    }
    if (jl_typeis(v, jl_linenumbernode_type)) {
        return fl_cons(julia_to_scm((jl_value_t*)line_sym),
                       fl_cons(julia_to_scm(jl_fieldref(v,0)),
                               FL_NIL));
    }
    if (jl_typeis(v, jl_labelnode_type)) {
        return fl_cons(julia_to_scm((jl_value_t*)label_sym),
                       fl_cons(julia_to_scm(jl_fieldref(v,0)),
                               FL_NIL));
    }
    if (jl_typeis(v, jl_gotonode_type)) {
        return fl_cons(julia_to_scm((jl_value_t*)goto_sym),
                       fl_cons(julia_to_scm(jl_fieldref(v,0)),
                               FL_NIL));
    }
    if (jl_typeis(v, jl_quotenode_type)) {
        return fl_cons(julia_to_scm((jl_value_t*)quote_sym),
                       fl_cons(julia_to_scm(jl_fieldref(v,0)),
                               FL_NIL));
    }
    if (jl_typeis(v, jl_topnode_type)) {
        return fl_cons(julia_to_scm((jl_value_t*)top_sym),
                       fl_cons(julia_to_scm(jl_fieldref(v,0)),
                               FL_NIL));
    }
    if (jl_is_long(v) && fits_fixnum(jl_unbox_long(v))) {
        return fixnum(jl_unbox_long(v));
    }
    if (jl_is_array(v)) {
        return array_to_list((jl_array_t*)v);
    }
    value_t opaque = cvalue(jvtype, sizeof(void*));
    *(jl_value_t**)cv_data((cvalue_t*)ptr(opaque)) = v;
    return opaque;
}

// this is used to parse a line of repl input
DLLEXPORT jl_value_t *jl_parse_input_line(const char *str)
{
    value_t e = fl_applyn(1, symbol_value(symbol("jl-parse-string")),
                          cvalue_static_cstring(str));
    if (e == FL_T || e == FL_F || e == FL_EOF)
        return jl_nothing;
    
    return scm_to_julia(e);
}

// this is for parsing one expression out of a string, keeping track of
// the current position.
DLLEXPORT jl_value_t *jl_parse_string(const char *str, int pos0, int greedy)
{
    value_t s = cvalue_static_cstring(str);
    value_t p = fl_applyn(3, symbol_value(symbol("jl-parse-one-string")),
                          s, fixnum(pos0), greedy?FL_T:FL_F);
    jl_value_t *expr=NULL, *pos1=NULL;
    JL_GC_PUSH(&expr, &pos1);

    value_t e = car_(p);
    if (e == FL_T || e == FL_F || e == FL_EOF) {
        expr = (jl_value_t*)jl_null;
    }
    else {
        expr = scm_to_julia(e);
    }

    pos1 = jl_box_long(toulong(cdr_(p),"parse"));
    jl_value_t *result = (jl_value_t*)jl_tuple2(expr, pos1);
    JL_GC_POP();
    return result;
}

jl_value_t *jl_parse_file(const char *fname)
{
    value_t e = fl_applyn(1, symbol_value(symbol("jl-parse-file")),
                          cvalue_static_cstring(fname));
    if (!iscons(e))
        return (jl_value_t*)jl_null;
    return scm_to_julia(e);
}

void jl_load_file_string(const char *text)
{
    value_t e = fl_applyn(1, symbol_value(symbol("jl-parse-string-stream")),
                          cvalue_static_cstring(text));
    if (iscons(e)) {
        jl_value_t *fexpr = scm_to_julia(e);
        JL_GC_PUSH(&fexpr);
        jl_load_file_expr("string", fexpr);
        JL_GC_POP();
    }
}

// returns either an expression or a thunk
jl_value_t *jl_expand(jl_value_t *expr)
{
    int np = jl_gc_n_preserved_values();
    value_t e = fl_applyn(1, symbol_value(symbol("jl-expand-to-thunk")),
                          julia_to_scm(expr));
    jl_value_t *result;
    if (e == FL_T || e == FL_F || e == FL_EOF) {
        result = NULL;
    }
    else {
        result = scm_to_julia(e);
    }
    while (jl_gc_n_preserved_values() > np) {
        jl_gc_unpreserve();
    }
    return result;
}

// wrap expr in a thunk AST
jl_lambda_info_t *jl_wrap_expr(jl_value_t *expr)
{
    // `(lambda () (() () ()) ,expr)
    jl_expr_t *le=NULL, *bo=NULL; jl_value_t *vi=NULL;
    jl_value_t *mt = jl_an_empty_cell;
    JL_GC_PUSH(&le, &vi, &bo);
    le = jl_exprn(lambda_sym, 3);
    jl_cellset(le->args, 0, mt);
    vi = (jl_value_t*)jl_alloc_cell_1d(3);
    jl_cellset(vi, 0, mt);
    jl_cellset(vi, 1, mt);
    jl_cellset(vi, 2, mt);
    jl_cellset(le->args, 1, vi);
    if (!jl_is_expr(expr) || ((jl_expr_t*)expr)->head != body_sym) {
        bo = jl_exprn(body_sym, 1);
        jl_cellset(bo->args, 0, (jl_value_t*)jl_exprn(return_sym, 1));
        jl_cellset(((jl_expr_t*)jl_exprarg(bo,0))->args, 0, expr);
        expr = (jl_value_t*)bo;
    }
    jl_cellset(le->args, 2, expr);
    jl_lambda_info_t *li = jl_new_lambda_info((jl_value_t*)le, jl_null);
    JL_GC_POP();
    return li;
}

// syntax tree accessors

// get array of formal argument expressions
jl_array_t *jl_lam_args(jl_expr_t *l)
{
    assert(l->head == lambda_sym);
    jl_value_t *ae = jl_exprarg(l,0);
    assert(jl_is_array(ae));
    return (jl_array_t*)ae;
}

// get array of local var symbols
jl_array_t *jl_lam_locals(jl_expr_t *l)
{
    jl_value_t *le = jl_exprarg(l, 1);
    assert(jl_is_array(le));
    jl_value_t *ll = jl_cellref(le, 0);
    assert(jl_is_array(ll));
    return (jl_array_t*)ll;
}

// get array of var info records
jl_array_t *jl_lam_vinfo(jl_expr_t *l)
{
    jl_value_t *le = jl_exprarg(l, 1);
    assert(jl_is_array(le));
    jl_value_t *ll = jl_cellref(le, 1);
    assert(jl_is_array(ll));
    return (jl_array_t*)ll;
}

// get array of var info records for captured vars
jl_array_t *jl_lam_capt(jl_expr_t *l)
{
    if (jl_is_tuple(l)) {
        // in compressed form
        return (jl_array_t*)jl_tupleref(l, 3);
    }
    assert(jl_is_expr(l));
    jl_value_t *le = jl_exprarg(l, 1);
    assert(jl_is_array(le));
    jl_value_t *ll = jl_cellref(le, 2);
    assert(jl_is_array(ll));
    return (jl_array_t*)ll;
}

// get array of body forms
jl_expr_t *jl_lam_body(jl_expr_t *l)
{
    assert(jl_is_expr(l));
    jl_value_t *be = jl_exprarg(l, 2);
    assert(jl_is_expr(be));
    assert(((jl_expr_t*)be)->head == body_sym);
    return (jl_expr_t*)be;
}

jl_sym_t *jl_decl_var(jl_value_t *ex)
{
    if (jl_is_symbol(ex)) return (jl_sym_t*)ex;
    assert(jl_is_expr(ex));
    return (jl_sym_t*)jl_exprarg(ex, 0);
}

int jl_is_rest_arg(jl_value_t *ex)
{
    if (!jl_is_expr(ex)) return 0;
    if (((jl_expr_t*)ex)->head != colons_sym) return 0;
    jl_expr_t *atype = (jl_expr_t*)jl_exprarg(ex,1);
    if (!jl_is_expr(atype)) return 0;
    if (atype->head != call_sym || atype->args->length != 3)
        return 0;
    if ((jl_sym_t*)jl_exprarg(atype,1) != dots_sym)
        return 0;
    return 1;
}

static jl_value_t *copy_ast(jl_value_t *expr, jl_tuple_t *sp)
{
    if (jl_is_symbol(expr)) {
        // pre-evaluate certain static parameters to help type inference
        for(int i=0; i < sp->length; i+=2) {
            assert(jl_is_typevar(jl_tupleref(sp,i)));
            if ((jl_sym_t*)expr == ((jl_tvar_t*)jl_tupleref(sp,i))->name) {
                jl_value_t *spval = jl_tupleref(sp,i+1);
                if (jl_is_long(spval))
                    return spval;
            }
        }
    }
    else if (jl_is_lambda_info(expr)) {
        jl_lambda_info_t *li = (jl_lambda_info_t*)expr;
        /*
        if (sp == jl_null && li->ast &&
            jl_lam_capt((jl_expr_t*)li->ast)->length == 0)
            return expr;
        */
        // TODO: avoid if above condition is true and decls have already
        // been evaluated.
        JL_GC_PUSH(&li);
        li = jl_add_static_parameters(li, sp);
        li->ast = jl_prepare_ast(li, li->sparams);
        JL_GC_POP();
        return (jl_value_t*)li;
    }
    else if (jl_typeis(expr,jl_array_any_type)) {
        jl_array_t *a = (jl_array_t*)expr;
        jl_array_t *na = jl_alloc_cell_1d(a->length);
        JL_GC_PUSH(&na);
        size_t i;
        for(i=0; i < a->length; i++)
            jl_cellset(na, i, copy_ast(jl_cellref(a,i), sp));
        JL_GC_POP();
        return (jl_value_t*)na;
    }
    else if (jl_is_expr(expr)) {
        jl_expr_t *e = (jl_expr_t*)expr;
        jl_expr_t *ne = jl_exprn(e->head, e->args->length);
        JL_GC_PUSH(&ne);
        size_t i;
        for(i=0; i < e->args->length; i++)
            jl_exprarg(ne, i) = copy_ast(jl_exprarg(e,i), sp);
        JL_GC_POP();
        return (jl_value_t*)ne;
    }
    return expr;
}

// TODO: eval decl types for arguments of non-generic functions
static void eval_decl_types(jl_array_t *vi, jl_tuple_t *spenv)
{
    size_t i;
    for(i=0; i < vi->length; i++) {
        jl_array_t *v = (jl_array_t*)jl_cellref(vi, i);
        assert(v->length > 1);
        jl_value_t *ty =
            jl_interpret_toplevel_expr_with(jl_cellref(v,1),
                                            &jl_tupleref(spenv,0),
                                            spenv->length/2);
        jl_cellref(v, 1) = ty;
    }
}

jl_tuple_t *jl_tuple_tvars_to_symbols(jl_tuple_t *t)
{
    jl_tuple_t *s = jl_alloc_tuple_uninit(t->length);
    size_t i;
    for(i=0; i < s->length; i+=2) {
        assert(jl_is_typevar(jl_tupleref(t,i)));
        jl_tupleset(s, i,
                    (jl_value_t*)((jl_tvar_t*)jl_tupleref(t,i))->name);
        jl_tupleset(s, i+1, jl_tupleref(t,i+1));
    }
    return s;
}

// given a new lambda_info with static parameter values, make a copy
// of the tree with declared types evaluated and static parameters passed
// on to all enclosed functions.
// this tree can then be further mutated by optimization passes.
DLLEXPORT
jl_value_t *jl_prepare_ast(jl_lambda_info_t *li, jl_tuple_t *sparams)
{
    jl_tuple_t *spenv = NULL;
    jl_value_t *l_ast = li->ast;
    if (l_ast == NULL) return NULL;
    jl_value_t *ast = l_ast;
    JL_GC_PUSH(&spenv, &ast);
    if (jl_is_tuple(ast))
        ast = jl_uncompress_ast((jl_tuple_t*)ast);
    spenv = jl_tuple_tvars_to_symbols(sparams);
    ast = copy_ast(ast, sparams);
    eval_decl_types(jl_lam_vinfo((jl_expr_t*)ast), spenv);
    eval_decl_types(jl_lam_capt((jl_expr_t*)ast), spenv);
    JL_GC_POP();
    return ast;
}