parsermodule.c

python s60 1.4.5版本的源代码

    int res = (validate_ntype(tree, exec_stmt)
               && ((nch == 2) || (nch == 4) || (nch == 6))
               && validate_name(CHILD(tree, 0), "exec")
               && validate_expr(CHILD(tree, 1)));

    if (!res && !PyErr_Occurred())
        err_string("illegal exec statement");
    if (res && (nch > 2))
        res = (validate_name(CHILD(tree, 2), "in")
               && validate_test(CHILD(tree, 3)));
    if (res && (nch == 6))
        res = (validate_comma(CHILD(tree, 4))
               && validate_test(CHILD(tree, 5)));

    return (res);
}


/*  assert_stmt:
 *
 *  'assert' test [',' test]
 */
static int
validate_assert_stmt(node *tree)
{
    int nch = NCH(tree);
    int res = (validate_ntype(tree, assert_stmt)
               && ((nch == 2) || (nch == 4))
               && (validate_name(CHILD(tree, 0), "__assert__") ||
                   validate_name(CHILD(tree, 0), "assert"))
               && validate_test(CHILD(tree, 1)));

    if (!res && !PyErr_Occurred())
        err_string("illegal assert statement");
    if (res && (nch > 2))
        res = (validate_comma(CHILD(tree, 2))
               && validate_test(CHILD(tree, 3)));

    return (res);
}


static int
validate_while(node *tree)
{
    int nch = NCH(tree);
    int res = (validate_ntype(tree, while_stmt)
               && ((nch == 4) || (nch == 7))
               && validate_name(CHILD(tree, 0), "while")
               && validate_test(CHILD(tree, 1))
               && validate_colon(CHILD(tree, 2))
               && validate_suite(CHILD(tree, 3)));

    if (res && (nch == 7))
        res = (validate_name(CHILD(tree, 4), "else")
               && validate_colon(CHILD(tree, 5))
               && validate_suite(CHILD(tree, 6)));

    return (res);
}


static int
validate_for(node *tree)
{
    int nch = NCH(tree);
    int res = (validate_ntype(tree, for_stmt)
               && ((nch == 6) || (nch == 9))
               && validate_name(CHILD(tree, 0), "for")
               && validate_exprlist(CHILD(tree, 1))
               && validate_name(CHILD(tree, 2), "in")
               && validate_testlist(CHILD(tree, 3))
               && validate_colon(CHILD(tree, 4))
               && validate_suite(CHILD(tree, 5)));

    if (res && (nch == 9))
        res = (validate_name(CHILD(tree, 6), "else")
               && validate_colon(CHILD(tree, 7))
               && validate_suite(CHILD(tree, 8)));

    return (res);
}


/*  try_stmt:
 *      'try' ':' suite (except_clause ':' suite)+ ['else' ':' suite]
 *    | 'try' ':' suite 'finally' ':' suite
 *
 */
static int
validate_try(node *tree)
{
    int nch = NCH(tree);
    int pos = 3;
    int res = (validate_ntype(tree, try_stmt)
               && (nch >= 6) && ((nch % 3) == 0));

    if (res)
        res = (validate_name(CHILD(tree, 0), "try")
               && validate_colon(CHILD(tree, 1))
               && validate_suite(CHILD(tree, 2))
               && validate_colon(CHILD(tree, nch - 2))
               && validate_suite(CHILD(tree, nch - 1)));
    else if (!PyErr_Occurred()) {
        const char* name = "except";
        if (TYPE(CHILD(tree, nch - 3)) != except_clause)
            name = STR(CHILD(tree, nch - 3));

        PyErr_Format(parser_error,
                     "Illegal number of children for try/%s node.", name);
    }
    /*  Skip past except_clause sections:  */
    while (res && (TYPE(CHILD(tree, pos)) == except_clause)) {
        res = (validate_except_clause(CHILD(tree, pos))
               && validate_colon(CHILD(tree, pos + 1))
               && validate_suite(CHILD(tree, pos + 2)));
        pos += 3;
    }
    if (res && (pos < nch)) {
        res = validate_ntype(CHILD(tree, pos), NAME);
        if (res && (strcmp(STR(CHILD(tree, pos)), "finally") == 0))
            res = (validate_numnodes(tree, 6, "try/finally")
                   && validate_colon(CHILD(tree, 4))
                   && validate_suite(CHILD(tree, 5)));
        else if (res) {
            if (nch == (pos + 3)) {
                res = ((strcmp(STR(CHILD(tree, pos)), "except") == 0)
                       || (strcmp(STR(CHILD(tree, pos)), "else") == 0));
                if (!res)
                    err_string("illegal trailing triple in try statement");
            }
            else if (nch == (pos + 6)) {
                res = (validate_name(CHILD(tree, pos), "except")
                       && validate_colon(CHILD(tree, pos + 1))
                       && validate_suite(CHILD(tree, pos + 2))
                       && validate_name(CHILD(tree, pos + 3), "else"));
            }
            else
                res = validate_numnodes(tree, pos + 3, "try/except");
        }
    }
    return (res);
}


static int
validate_except_clause(node *tree)
{
    int nch = NCH(tree);
    int res = (validate_ntype(tree, except_clause)
               && ((nch == 1) || (nch == 2) || (nch == 4))
               && validate_name(CHILD(tree, 0), "except"));

    if (res && (nch > 1))
        res = validate_test(CHILD(tree, 1));
    if (res && (nch == 4))
        res = (validate_comma(CHILD(tree, 2))
               && validate_test(CHILD(tree, 3)));

    return (res);
}


static int
validate_test(node *tree)
{
    int nch = NCH(tree);
    int res = validate_ntype(tree, test) && is_odd(nch);

    if (res && (TYPE(CHILD(tree, 0)) == lambdef))
        res = ((nch == 1)
               && validate_lambdef(CHILD(tree, 0)));
    else if (res) {
        int pos;
        res = validate_and_test(CHILD(tree, 0));
        for (pos = 1; res && (pos < nch); pos += 2)
            res = (validate_name(CHILD(tree, pos), "or")
                   && validate_and_test(CHILD(tree, pos + 1)));
    }
    return (res);
}


static int
validate_and_test(node *tree)
{
    int pos;
    int nch = NCH(tree);
    int res = (validate_ntype(tree, and_test)
               && is_odd(nch)
               && validate_not_test(CHILD(tree, 0)));

    for (pos = 1; res && (pos < nch); pos += 2)
        res = (validate_name(CHILD(tree, pos), "and")
               && validate_not_test(CHILD(tree, 0)));

    return (res);
}


static int
validate_not_test(node *tree)
{
    int nch = NCH(tree);
    int res = validate_ntype(tree, not_test) && ((nch == 1) || (nch == 2));

    if (res) {
        if (nch == 2)
            res = (validate_name(CHILD(tree, 0), "not")
                   && validate_not_test(CHILD(tree, 1)));
        else if (nch == 1)
            res = validate_comparison(CHILD(tree, 0));
    }
    return (res);
}


static int
validate_comparison(node *tree)
{
    int pos;
    int nch = NCH(tree);
    int res = (validate_ntype(tree, comparison)
               && is_odd(nch)
               && validate_expr(CHILD(tree, 0)));

    for (pos = 1; res && (pos < nch); pos += 2)
        res = (validate_comp_op(CHILD(tree, pos))
               && validate_expr(CHILD(tree, pos + 1)));

    return (res);
}


static int
validate_comp_op(node *tree)
{
    int res = 0;
    int nch = NCH(tree);

    if (!validate_ntype(tree, comp_op))
        return (0);
    if (nch == 1) {
        /*
         *  Only child will be a terminal with a well-defined symbolic name
         *  or a NAME with a string of either 'is' or 'in'
         */
        tree = CHILD(tree, 0);
        switch (TYPE(tree)) {
            case LESS:
            case GREATER:
            case EQEQUAL:
            case EQUAL:
            case LESSEQUAL:
            case GREATEREQUAL:
            case NOTEQUAL:
              res = 1;
              break;
            case NAME:
              res = ((strcmp(STR(tree), "in") == 0)
                     || (strcmp(STR(tree), "is") == 0));
              if (!res) {
                  PyErr_Format(parser_error,
                               "illegal operator '%s'", STR(tree));
              }
              break;
          default:
              err_string("illegal comparison operator type");
              break;
        }
    }
    else if ((res = validate_numnodes(tree, 2, "comp_op")) != 0) {
        res = (validate_ntype(CHILD(tree, 0), NAME)
               && validate_ntype(CHILD(tree, 1), NAME)
               && (((strcmp(STR(CHILD(tree, 0)), "is") == 0)
                    && (strcmp(STR(CHILD(tree, 1)), "not") == 0))
                   || ((strcmp(STR(CHILD(tree, 0)), "not") == 0)
                       && (strcmp(STR(CHILD(tree, 1)), "in") == 0))));
        if (!res && !PyErr_Occurred())
            err_string("unknown comparison operator");
    }
    return (res);
}


static int
validate_expr(node *tree)
{
    int j;
    int nch = NCH(tree);
    int res = (validate_ntype(tree, expr)
               && is_odd(nch)
               && validate_xor_expr(CHILD(tree, 0)));

    for (j = 2; res && (j < nch); j += 2)
        res = (validate_xor_expr(CHILD(tree, j))
               && validate_vbar(CHILD(tree, j - 1)));

    return (res);
}


static int
validate_xor_expr(node *tree)
{
    int j;
    int nch = NCH(tree);
    int res = (validate_ntype(tree, xor_expr)
               && is_odd(nch)
               && validate_and_expr(CHILD(tree, 0)));

    for (j = 2; res && (j < nch); j += 2)
        res = (validate_circumflex(CHILD(tree, j - 1))
               && validate_and_expr(CHILD(tree, j)));

    return (res);
}


static int
validate_and_expr(node *tree)
{
    int pos;
    int nch = NCH(tree);
    int res = (validate_ntype(tree, and_expr)
               && is_odd(nch)
               && validate_shift_expr(CHILD(tree, 0)));

    for (pos = 1; res && (pos < nch); pos += 2)
        res = (validate_ampersand(CHILD(tree, pos))
               && validate_shift_expr(CHILD(tree, pos + 1)));

    return (res);
}


static int
validate_chain_two_ops(node *tree, int (*termvalid)(node *), int op1, int op2)
 {
    int pos = 1;
    int nch = NCH(tree);
    int res = (is_odd(nch)
               && (*termvalid)(CHILD(tree, 0)));

    for ( ; res && (pos < nch); pos += 2) {
        if (TYPE(CHILD(tree, pos)) != op1)
            res = validate_ntype(CHILD(tree, pos), op2);
        if (res)
            res = (*termvalid)(CHILD(tree, pos + 1));
    }
    return (res);
}


static int
validate_shift_expr(node *tree)
{
    return (validate_ntype(tree, shift_expr)
            && validate_chain_two_ops(tree, validate_arith_expr,
                                      LEFTSHIFT, RIGHTSHIFT));
}


static int
validate_arith_expr(node *tree)
{
    return (validate_ntype(tree, arith_expr)
            && validate_chain_two_ops(tree, validate_term, PLUS, MINUS));
}


static int
validate_term(node *tree)
{
    int pos = 1;
    int nch = NCH(tree);
    int res = (validate_ntype(tree, term)
               && is_odd(nch)
               && validate_factor(CHILD(tree, 0)));

    for ( ; res && (pos < nch); pos += 2)
        res = (((TYPE(CHILD(tree, pos)) == STAR)
               || (TYPE(CHILD(tree, pos)) == SLASH)
               || (TYPE(CHILD(tree, pos)) == PERCENT))
               && validate_factor(CHILD(tree, pos + 1)));

    return (res);
}


/*  factor:
 *
 *  factor: ('+'|'-'|'~') factor | power
 */
static int
validate_factor(node *tree)
{
    int nch = NCH(tree);
    int res = (validate_ntype(tree, factor)
               && (((nch == 2)
                    && ((TYPE(CHILD(tree, 0)) == PLUS)
                        || (TYPE(CHILD(tree, 0)) == MINUS)
                        || (TYPE(CHILD(tree, 0)) == TILDE))
                    && validate_factor(CHILD(tree, 1)))
                   || ((nch == 1)
                       && validate_power(CHILD(tree, 0)))));
    return (res);
}


/*  power:
 *
 *  power: atom trailer* ('**' factor)*
 */
static int
validate_power(node *tree)
{
    int pos = 1;
    int nch = NCH(tree);
    int res = (validate_ntype(tree, power) && (nch >= 1)
               && validate_atom(CHILD(tree, 0)));

    while (res && (pos < nch) && (TYPE(CHILD(tree, pos)) == trailer))
        res = validate_trailer(CHILD(tree, pos++));
    if (res && (pos < nch)) {
        if (!is_even(nch - pos)) {
            err_string("illegal number of nodes for 'power'");
            retu