rt-thread-official/finsh/finsh_parser.c

#include <finsh.h>

#include "finsh_token.h"
#include "finsh_node.h"
#include "finsh_error.h"
#include "finsh_parser.h"
#include "finsh_var.h"

/*
 * the structure of abstract syntax tree:
 * root____________
 * |               \
 * child__        sibling__
 * |      \       |        \
 * child sibling  child   sibling
 *                          ...
 */
static enum finsh_type proc_type(struct finsh_parser* self);
static int proc_identifier(struct finsh_parser* self, char* id);
static struct finsh_node* proc_variable_decl(struct finsh_parser* self);
static struct finsh_node* proc_expr(struct finsh_parser* self);
static struct finsh_node* proc_assign_expr(struct finsh_parser* self);
static struct finsh_node* proc_inclusive_or_expr(struct finsh_parser* self);
static struct finsh_node* proc_exclusive_or_expr(struct finsh_parser* self);
static struct finsh_node* proc_and_expr(struct finsh_parser* self);
static struct finsh_node* proc_shift_expr(struct finsh_parser* self);
static struct finsh_node* proc_additive_expr(struct finsh_parser* self);
static struct finsh_node* proc_multiplicative_expr(struct finsh_parser* self);
static struct finsh_node* proc_cast_expr(struct finsh_parser* self);
static struct finsh_node* proc_unary_expr(struct finsh_parser* self);
static struct finsh_node* proc_postfix_expr(struct finsh_parser* self);
static struct finsh_node* proc_primary_expr(struct finsh_parser* self);
static struct finsh_node* proc_param_list(struct finsh_parser* self);
static struct finsh_node* proc_expr_statement(struct finsh_parser* self);
static struct finsh_node* make_sys_node(u_char type, struct finsh_node* node1,
	struct finsh_node* node2);

/* check token */
#define check_token(token, lex, type) if ( (token) != (type) ) \
	{ \
		finsh_error_set(FINSH_ERROR_INVALID_TOKEN); \
		finsh_token_replay(lex); \
	}

/* is the token a data type? */
#define is_base_type(token)	((token) == finsh_token_type_void \
    || (token) == finsh_token_type_char \
	|| (token) == finsh_token_type_short \
	|| (token) == finsh_token_type_int \
	|| (token) == finsh_token_type_long)

/* get the next token */
#define next_token(token, lex)	(token) = finsh_token_token(lex)

/* match a specified token */
#define match_token(token, lex, type)	next_token(token, lex); \
	check_token(token, lex, type)

/*
process for function and variable declaration.
decl_variable -> type declaration_list ';'
declarator_list -> declarator_list ',' declarator
	| declarator
declarator -> identifier
	| identifier ASSIGN expr_assign
*/
static struct finsh_node* proc_variable_decl(struct finsh_parser* self)
{
	enum finsh_token_type token;
	enum finsh_type type;
	char id[FINSH_NAME_MAX + 1];

	struct finsh_node *node;
	struct finsh_node *end;
	struct finsh_node *assign;

    node = NULL;
	end  = NULL;

	/* get type */
	type = proc_type(self);

	/*process id.*/
	if (proc_identifier(self, id) == 0)
	{
		/* if add variable failed */
		if (finsh_var_insert(id, type) < 0)
		{
			finsh_error_set(FINSH_ERROR_VARIABLE_EXIST);
		}
	}

	next_token(token, &(self->token));
	switch ( token )
	{
	case finsh_token_type_comma:/*',', it's a variable_list declaration.*/
		if (proc_identifier(self, id) == 0)
		{
			/* if add variable failed */
			if (finsh_var_insert(id, type) < 0)
			{
				finsh_error_set(FINSH_ERROR_VARIABLE_EXIST);
			}
		}

		next_token(token, &(self->token));
		if ( token == finsh_token_type_assign )
		{
			/* get the right side of assign expression */
			assign = proc_assign_expr(self);

			if (assign != NULL)
			{
				struct finsh_node* idnode;

				idnode = finsh_node_new_id(id);
				end = make_sys_node(FINSH_NODE_SYS_ASSIGN, idnode, assign);
				node = end;

				next_token(token, &(self->token));
			}
		}

		while ( token == finsh_token_type_comma )
		{
			if (proc_identifier(self, id) == 0)
			{
				/* if add variable failed */
				if (finsh_var_insert(id, type) < 0)
				{
					finsh_error_set(FINSH_ERROR_VARIABLE_EXIST);
				}
			}

			next_token(token, &(self->token));
			if ( token == finsh_token_type_assign )
			{
				/* get the right side of assign expression */
				assign = proc_assign_expr(self);

				if (assign != NULL)
				{
					struct finsh_node* idnode;

					idnode = finsh_node_new_id(id);

					/* make assign expression node */
					if (node != NULL)
					{
						finsh_node_sibling(end) = make_sys_node(FINSH_NODE_SYS_ASSIGN, idnode, assign);
						end = finsh_node_sibling(end);
					}
					else
					{
						end = make_sys_node(FINSH_NODE_SYS_ASSIGN, idnode, assign);
						node = end;
					}

					next_token(token, &(self->token));
				}
			}
		}

		check_token(token, &(self->token), finsh_token_type_semicolon);
		return node;

	case finsh_token_type_assign:/*'=', it's a variable with assign declaration.*/
	{
		struct finsh_node *idnode;

		assign = proc_assign_expr(self);
		if (assign != NULL)
		{
			idnode = finsh_node_new_id(id);

			/* make assign expression node */
			end = make_sys_node(FINSH_NODE_SYS_ASSIGN, idnode, assign);
			node = end;

			next_token(token, &(self->token));
		}

		while ( token == finsh_token_type_comma )
		{
			if (proc_identifier(self, id) == 0)
			{
				/* if add variable failed */
				if (finsh_var_insert(id, type) < 0)
				{
					finsh_error_set(FINSH_ERROR_VARIABLE_EXIST);
				}
			}

			next_token(token, &(self->token));
			if (token == finsh_token_type_assign)
			{
				/* get the right side of assign expression */
				assign = proc_assign_expr(self);

				if (assign != NULL)
				{
					idnode = finsh_node_new_id(id);

					/* make assign expression node */
					if (node != NULL)
					{
						finsh_node_sibling(end) = make_sys_node(FINSH_NODE_SYS_ASSIGN, idnode, assign);
						end = finsh_node_sibling(end);
					}
					else
					{
						end = make_sys_node(FINSH_NODE_SYS_ASSIGN, idnode, assign);
						node = end;
					}

					next_token(token, &(self->token));
				}
			}
		}

		check_token(token, &(self->token), finsh_token_type_semicolon);
		return node;
	}

	case finsh_token_type_semicolon:/*';', it's a variable declaration.*/
		return node;

	default:
		finsh_error_set(FINSH_ERROR_EXPECT_TYPE);

		return NULL;
	}
}

/*
type -> type_prefix type_basic | type_basic
type_prefix -> UNSIGNED
type_basic -> VOID
	| CHAR
	| SHORT
	| INT
	| STRING
*/
static enum finsh_type proc_type(struct finsh_parser* self)
{
	enum finsh_type type;
	enum finsh_token_type token;

	/* set init type */
	type = finsh_type_unknown;

	next_token(token, &(self->token));
	if ( is_base_type(token) ) /* base_type */
	{
		switch (token)
		{
		case finsh_token_type_void:
			type = finsh_type_void;
			break;

		case finsh_token_type_char:
			type = finsh_type_char;
			break;

		case finsh_token_type_short:
			type = finsh_type_short;
			break;

		case finsh_token_type_int:
			type = finsh_type_int;
			break;

		case finsh_token_type_long:
			type = finsh_type_long;
			break;

		default:
			goto __return;
		}
	}
	else if ( token == finsh_token_type_unsigned ) /* unsigned base_type */
	{
		next_token(token, &(self->token));
		if ( is_base_type(token) )
		{
			switch (token)
			{
			case finsh_token_type_char:
				type = finsh_type_uchar;
				break;

			case finsh_token_type_short:
				type = finsh_type_ushort;
				break;

			case finsh_token_type_int:
				type = finsh_type_uint;
				break;

			case finsh_token_type_long:
				type = finsh_type_ulong;
				break;

			default:
				goto __return;
			}
		}
		else
		{
			finsh_token_replay(&(self->token));
			finsh_error_set(FINSH_ERROR_EXPECT_TYPE);
		}
	}
	else
	{
		goto __return;
	}

	/* parse for pointer */
	next_token(token, &(self->token));
	if (token == finsh_token_type_mul)
	{
		switch (type)
		{
		case finsh_type_void:
			type = finsh_type_voidp;
			break;

		case finsh_type_char:
		case finsh_type_uchar:
			type = finsh_type_charp;
			break;

		case finsh_type_short:
		case finsh_type_ushort:
			type = finsh_type_shortp;
			break;

		case finsh_type_int:
		case finsh_type_uint:
			type = finsh_type_intp;
			break;

		case finsh_type_long:
		case finsh_type_ulong:
			type = finsh_type_longp;
			break;

		default:
			type = finsh_type_voidp;
			break;
		}
	}
	else finsh_token_replay(&(self->token));

	return type;

__return:
	finsh_token_replay(&(self->token));
	finsh_error_set(FINSH_ERROR_UNKNOWN_TYPE);

	return type;
}

/*
identifier -> IDENTIFIER
*/
static int proc_identifier(struct finsh_parser* self, char* id)
{
	enum finsh_token_type token;

	match_token(token, &(self->token), finsh_token_type_identifier);

	strncpy(id, (char*)self->token.string, FINSH_NAME_MAX);

	return 0;
}

/*
statement_expr -> ';'
	| expr ';'
*/
static struct finsh_node* proc_expr_statement(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* expr;

	expr = NULL;
	next_token(token, &(self->token));
	if ( token != finsh_token_type_semicolon )
	{
		finsh_token_replay(&(self->token));
		expr = proc_expr(self);

		match_token(token, &(self->token), finsh_token_type_semicolon);
	}

	return expr;
}

/*
expr -> expr_assign
*/
static struct finsh_node* proc_expr(struct finsh_parser* self)
{
	return proc_assign_expr(self);
}

/*
expr_assign -> expr_inclusive_or
	| expr_unary ASSIGN expr_assign
*/
static struct finsh_node* proc_assign_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* or;
	struct finsh_node* assign;

	or = proc_inclusive_or_expr(self);

	next_token(token, &(self->token));

	if (token == finsh_token_type_assign)
	{
		assign = proc_assign_expr(self);

		return make_sys_node(FINSH_NODE_SYS_ASSIGN, or, assign);
	}
	else finsh_token_replay(&(self->token));

	return or;
}

/*
expr_inclusive_or -> expr_exclusive_or
	| expr_inclusive_or '|' expr_exclusive_or
*/
static struct finsh_node* proc_inclusive_or_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* xor;
	struct finsh_node* xor_new;

	xor = proc_exclusive_or_expr(self);

	next_token(token, &(self->token));
	while ( token == finsh_token_type_or )
	{
		xor_new = proc_exclusive_or_expr(self);

		if (xor_new == NULL) finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
		else xor = make_sys_node(FINSH_NODE_SYS_OR, xor, xor_new);

		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));
	return xor;
}

/*
expr_exclusive_or -> expr_and
	| expr_exclusive '^' expr_and
*/
static struct finsh_node* proc_exclusive_or_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* and;
	struct finsh_node* and_new;

	and = proc_and_expr(self);
	next_token(token, &(self->token));
	while ( token == finsh_token_type_xor )
	{
		and_new = proc_and_expr(self);
		if (and_new == NULL) finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
		else and = make_sys_node(FINSH_NODE_SYS_XOR, and, and_new);

		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));
	return and;
}

/*
expr_and -> expr_shift
	| expr_and '&' expr_shift
*/
static struct finsh_node* proc_and_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* shift;
	struct finsh_node* shift_new;

	shift = proc_shift_expr(self);

	next_token(token, &(self->token));
	while ( token == finsh_token_type_and )
	{
		shift_new = proc_shift_expr(self);

		if (shift_new == NULL) finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
		else shift = make_sys_node(FINSH_NODE_SYS_AND, shift, shift_new);

		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));
	return shift;
}

/*
expr_shift -> expr_additive
	| expr_shift '<<' expr_additive
	| expr_shift '>>' expr_additive
*/
static struct finsh_node* proc_shift_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* add;
	struct finsh_node* add_new;

	add = proc_additive_expr(self);

	next_token(token, &(self->token));
	while ( token == finsh_token_type_shl || token == finsh_token_type_shr)
	{
		add_new = proc_additive_expr(self);
		if (add_new == NULL) finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
		else
		{
			switch (token)
			{
			case finsh_token_type_shl:
				add = make_sys_node(FINSH_NODE_SYS_SHL, add, add_new);
				break;
			case finsh_token_type_shr:
				add = make_sys_node(FINSH_NODE_SYS_SHR, add, add_new);
				break;
			default:
				finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
				break;
			}
		}
		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));
	return add;
}

/*
expr_additive -> expr_multiplicative
	| expr_additive SUB expr_multiplicative
	| expr_additive ADD expr_multiplicative
*/
static struct finsh_node* proc_additive_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* mul;
	struct finsh_node* mul_new;

	mul = proc_multiplicative_expr(self);

	next_token(token, &(self->token));
	while ( token == finsh_token_type_sub || token == finsh_token_type_add )
	{
		mul_new = proc_multiplicative_expr(self);
		if (mul_new == NULL) finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
		else
		{
			switch (token)
			{
			case finsh_token_type_sub:
				mul = make_sys_node(FINSH_NODE_SYS_SUB, mul, mul_new);
				break;
			case finsh_token_type_add:
				mul = make_sys_node(FINSH_NODE_SYS_ADD, mul, mul_new);
				break;
			default:
				finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
				break;
			}
		}
		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));
	return mul;
}

/*
expr_multiplicative -> expr_cast
	| expr_multiplicative '*' expr_cast
	| expr_multiplicative '/' expr_cast
	| expr_multiplicative '%' expr_cast
*/
static struct finsh_node* proc_multiplicative_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* cast;
	struct finsh_node* cast_new;

	cast = proc_cast_expr(self);
	next_token(token, &(self->token));
	while (token == finsh_token_type_mul ||
		token == finsh_token_type_div ||
		token == finsh_token_type_mod )
	{
		cast_new = proc_cast_expr(self);
		if (cast_new == NULL) finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
		else
		{
			switch (token)
			{
			case finsh_token_type_mul:
				cast = make_sys_node(FINSH_NODE_SYS_MUL, cast, cast_new);
				break;

			case finsh_token_type_div:
				cast = make_sys_node(FINSH_NODE_SYS_DIV, cast, cast_new);
				break;

			case finsh_token_type_mod:
				cast = make_sys_node(FINSH_NODE_SYS_MOD, cast, cast_new);
				break;

			default:
				finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);
				break;
			}
		}
		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));
	return cast;
}

/*
20060313, add recast parse
expr_cast -> expr_unary
	| '(' type ')' expr_cast
*/
static struct finsh_node* proc_cast_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	enum finsh_type type;
	struct finsh_node* cast;

	next_token(token, &(self->token));
	if (token == finsh_token_type_left_paren)
	{
		type = proc_type(self);
		match_token(token, &(self->token), finsh_token_type_right_paren);

		cast = proc_cast_expr(self);
		if (cast != NULL)
		{
			cast->data_type = type;
			return cast;
		}
	}

	finsh_token_replay(&(self->token));
	return proc_unary_expr(self);
}

/*
20050921, add '*' and '&'
expr_unary -> expr_postfix
	| ADD expr_cast
	| INC expr_cast
	| SUB expr_cast
	| DEC expr_cast
	| '~' expr_cast
	| '*' expr_cast
	| '&' expr_cast
*/
static struct finsh_node* proc_unary_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node *cast;

	next_token(token, &(self->token));
	switch (token)
	{
	case finsh_token_type_add: /* + */
		cast = proc_cast_expr(self);
		return cast;

	case finsh_token_type_inc: /* ++ */
		cast = proc_cast_expr(self);
		return make_sys_node(FINSH_NODE_SYS_PREINC, cast, NULL);

	case finsh_token_type_sub: /* - */
		cast = proc_cast_expr(self);
		return make_sys_node(FINSH_NODE_SYS_SUB, finsh_node_new_long(0), cast);

	case finsh_token_type_dec: /* -- */
		cast = proc_cast_expr(self);
		return make_sys_node(FINSH_NODE_SYS_PREDEC, cast, NULL);

	case finsh_token_type_bitwise: /* ~ */
		cast = proc_cast_expr(self);
		return make_sys_node(FINSH_NODE_SYS_BITWISE, cast, NULL);

    case finsh_token_type_mul: /* * */
        cast = proc_cast_expr(self);
        return make_sys_node(FINSH_NODE_SYS_GETVALUE, cast, NULL);

    case finsh_token_type_and: /* & */
        cast = proc_cast_expr(self);
        return make_sys_node(FINSH_NODE_SYS_GETADDR, cast, NULL);

	default:
		finsh_token_replay(&(self->token));
		return proc_postfix_expr(self);
	}
}

/*
expr_postfix -> expr_primary
	| expr_postfix INC
	| expr_postfix DEC
	| expr_postfix '(' param_list ')'
*/
static struct finsh_node* proc_postfix_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* postfix;

	postfix = proc_primary_expr(self);

	next_token(token, &(self->token));
	while ( token == finsh_token_type_inc 	||
		token == finsh_token_type_dec 		||
		token == finsh_token_type_left_paren )
	{
		switch (token)
		{
		case finsh_token_type_inc :/* '++' */
			postfix = make_sys_node(FINSH_NODE_SYS_INC, postfix, NULL);
			break;

		case finsh_token_type_dec :/* '--' */
			postfix = make_sys_node(FINSH_NODE_SYS_DEC, postfix, NULL);
			break;

		case finsh_token_type_left_paren :/* '(' */
			{
				struct finsh_node* param_list;

				param_list = NULL;
				next_token(token, &(self->token));
				if (token != finsh_token_type_right_paren)
				{
					finsh_token_replay(&(self->token));
					param_list = proc_param_list(self);

					match_token(token, &(self->token), finsh_token_type_right_paren);
				}

				postfix = make_sys_node(FINSH_NODE_SYS_FUNC, postfix, param_list);
			}
			break;

		default:
			break;
		}

		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));
	return postfix;
}

/*
expr_primary -> literal
	| '(' expr ')'
	| identifier
*/
static struct finsh_node* proc_primary_expr(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node* expr;

	next_token(token, &(self->token));
	switch ( token )
	{
	case finsh_token_type_identifier:
		{
			char id[FINSH_NAME_MAX + 1];

			finsh_token_replay(&(self->token));
			proc_identifier(self, id);
			return finsh_node_new_id(id);
		}

	case finsh_token_type_left_paren:
		expr = proc_expr(self);
		match_token(token, &(self->token), finsh_token_type_right_paren);
		return expr;

	case finsh_token_type_value_int:
		return finsh_node_new_int(self->token.value.int_value);

	case finsh_token_type_value_long:
		return finsh_node_new_long(self->token.value.long_value);

	case finsh_token_type_value_char:
		return finsh_node_new_char(self->token.value.char_value);

	case finsh_token_type_value_string:
		return finsh_node_new_string((char*)self->token.string);

	case finsh_token_type_value_null:
		return finsh_node_new_ptr(NULL);

	default:
		finsh_error_set(FINSH_ERROR_INVALID_TOKEN);
		break;
	}

	return NULL;
}

/*
param_list -> empty
	| expr_assign
	| param_list ',' expr_assign
*/
static struct finsh_node* proc_param_list(struct finsh_parser* self)
{
	enum finsh_token_type token;
	struct finsh_node *node, *assign;

	assign = proc_assign_expr(self);
	if (assign == NULL) return NULL;
	node = assign;

	next_token(token, &(self->token));
	while (token == finsh_token_type_comma )
	{
		finsh_node_sibling(assign) = proc_assign_expr(self);

		if (finsh_node_sibling(assign) != NULL)	assign = finsh_node_sibling(assign);
		else finsh_error_set(FINSH_ERROR_EXPECT_OPERATOR);

		next_token(token, &(self->token));
	}

	finsh_token_replay(&(self->token));

	return node;
}

/*
make a new node as following tree:
new_node
|
node1__
       \
       node2
*/
static struct finsh_node* make_sys_node(u_char type, struct finsh_node* node1, struct finsh_node* node2)
{
	struct finsh_node* node;

	node = finsh_node_allocate(type);

	if (node1 != NULL)
	{
		finsh_node_child(node) = node1;
		finsh_node_sibling(node1) = node2;
	}
	else finsh_error_set(FINSH_ERROR_NULL_NODE);

	return node;
}

/*
start -> statement_expr | decl_variable
*/
void finsh_parser_run(struct finsh_parser* self, const u_char* string)
{
	enum finsh_token_type token;
	struct finsh_node *node;

    node = NULL;

	/* init parser */
	self->parser_string = (u_char*)string;

	/* init token */
	finsh_token_init(&(self->token), self->parser_string);

	/* get next token */
	next_token(token, &(self->token));
	while (token != finsh_token_type_eof && token != finsh_token_type_bad)
	{
		switch (token)
		{
        case finsh_token_type_identifier:
            /* process expr_statement */
            finsh_token_replay(&(self->token));

			if (self->root != NULL)
			{
				finsh_node_sibling(node) = proc_expr_statement(self);
				if (finsh_node_sibling(node) != NULL)
					node = finsh_node_sibling(node);
			}
			else
			{
            	node = proc_expr_statement(self);
				self->root = node;
			}
            break;

		default:
            if (is_base_type(token) || token == finsh_token_type_unsigned)
            {
            	/* variable decl */
            	finsh_token_replay(&(self->token));

				if (self->root != NULL)
				{
					finsh_node_sibling(node) = proc_variable_decl(self);
					if (finsh_node_sibling(node) != NULL)
						node = finsh_node_sibling(node);
				}
				else
				{
					node = proc_variable_decl(self);
					self->root = node;
				}
            }
            else
            {
            	/* process expr_statement */
                finsh_token_replay(&(self->token));

				if (self->root != NULL)
				{
                    finsh_node_sibling(node) = proc_expr_statement(self);
					if (finsh_node_sibling(node) != NULL)
						node = finsh_node_sibling(node);
					else next_token(token, &(self->token));
				}
				else
				{
					node = proc_expr_statement(self);
					self->root = node;
				}
            }

			break;
		}
        /* get next token */
		next_token(token, &(self->token));
	}
}

int finsh_parser_init(struct finsh_parser* self)
{
	memset(self, 0, sizeof(struct finsh_parser));

	return 0;
}