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issue #98 fix bug - final return not handled correctly, and ensure on parser failure error message is pushed as a second value after nil

Browse Source
pull/168/head
Dibyendu Majumdar 5 years ago
parent 90bb58272f
commit 74e8c76f5a
2 changed files with 62 additions and 46 deletions
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20
ravi-tests/ast_upvaltest.lua
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@ -1,6 +1,6 @@
function x()
local a = 1
local str =
[[return function()
local a = 1
local function y()
return function()
@ -18,10 +18,14 @@ function x()
return y, z
end
]]
--local y, z = x()
local y, z = x()
print(y()())
print(z()())
--print(y()())
--print(z()())
ravi.dumplua(x)
--ravi.dumplua(x)
local x, msg = ast.parse(str)
if not x then print(msg) end
print(x:tostring())
--print(x)

88
src/ravi_ast.c
Unescape View File

@ -420,26 +420,26 @@ static struct lua_symbol *search_for_variable_in_block(struct block_scope *scope
return NULL;
}
static struct lua_symbol *search_for_label_in_block(struct block_scope *scope, const TString *name) {
struct lua_symbol *symbol;
// Lookup in reverse order so that we discover the
// most recently added local symbol - as Lua allows same
// symbol to be declared local more than once in a scope
// Should also work with nesting as the function when parsed
// will only know about vars declared in parent function until
// now.
FOR_EACH_PTR_REVERSE(scope->symbol_list, symbol) {
switch (symbol->symbol_type) {
case SYM_LABEL: {
if (name == symbol->var.var_name) { return symbol; }
break;
}
default: break;
}
}
END_FOR_EACH_PTR_REVERSE(symbol);
return NULL;
}
//static struct lua_symbol *search_for_label_in_block(struct block_scope *scope, const TString *name) {
// struct lua_symbol *symbol;
// // Lookup in reverse order so that we discover the
// // most recently added local symbol - as Lua allows same
// // symbol to be declared local more than once in a scope
// // Should also work with nesting as the function when parsed
// // will only know about vars declared in parent function until
// // now.
// FOR_EACH_PTR_REVERSE(scope->symbol_list, symbol) {
// switch (symbol->symbol_type) {
// case SYM_LABEL: {
// if (name == symbol->var.var_name) { return symbol; }
// break;
// }
// default: break;
// }
// }
// END_FOR_EACH_PTR_REVERSE(symbol);
// return NULL;
//}
/* Each function has a list of upvalues, searches this list for given name
*/
@ -485,9 +485,11 @@ static bool add_upvalue_in_function(struct parser_state *parser, struct ast_node
}
/* Searches for a variable starting from current scope, and going up the
* scope chain. If not found and search_globals_too is requested then
* also searches the external symbols
/* Searches for a variable starting from current scope, going up the
* scope chain within the current function. If the variable is not found in any scope of the function, then
* search the function's upvalue list. Repeat the exercise in parent function until either
* the symbol is found or we exhaust the search. NULL is returned if search was
* exhausted.
*/
static struct lua_symbol *search_for_variable(struct parser_state *parser, const TString *varname) {
struct block_scope *current_scope = parser->current_scope;
@ -509,18 +511,18 @@ static struct lua_symbol *search_for_variable(struct parser_state *parser, const
/* Searches for a label in current function
*/
static struct lua_symbol *search_for_label(struct parser_state *parser, const TString *name) {
struct block_scope *current_scope = parser->current_scope;
while (current_scope && current_scope->function == parser->current_function) {
struct lua_symbol *symbol = search_for_label_in_block(current_scope, name);
if (symbol) return symbol;
current_scope = current_scope->parent;
}
return NULL;
}
//static struct lua_symbol *search_for_label(struct parser_state *parser, const TString *name) {
// struct block_scope *current_scope = parser->current_scope;
// while (current_scope && current_scope->function == parser->current_function) {
// struct lua_symbol *symbol = search_for_label_in_block(current_scope, name);
// if (symbol) return symbol;
// current_scope = current_scope->parent;
// }
// return NULL;
//}
/* Adds an upvalue to current_function and its parents until var_function; var_function being where the symbol
* exists as a local. If the symbol is found in a functions upvalue list then there is no need to
* exists as a local or an upvalue. If the symbol is found in a function's upvalue list then there is no need to
* check parent functions.
*/
static void add_upvalue_in_levels_upto(struct parser_state *parser, struct ast_node *current_function, struct ast_node *var_function, struct lua_symbol *symbol) {
@ -541,19 +543,21 @@ static struct ast_node *new_symbol_reference(struct parser_state *parser) {
TString *varname = check_name_and_next(parser->ls);
struct lua_symbol *symbol = search_for_variable(parser, varname);
if (symbol) {
// we found a local or upvalue
if (symbol->symbol_type == SYM_LOCAL && symbol->var.block->function != parser->current_function) {
// If the local symbol occurred in a parent function then we
// need to construct an upvalue. Lua requires that the upvalue be
// added to all functions in the tree upto the function where the local
// added to all functions in the tree up to the function where the local
// is defined.
add_upvalue_in_levels_upto(parser, parser->current_function, symbol->var.block->function, symbol);
// Following search could be avoided if above returned
// TODO Following search could be avoided if above returned the symbol
symbol = search_upvalue_in_function(parser->current_function, varname);
}
else if (symbol->symbol_type == SYM_UPVALUE && symbol->upvalue.function != parser->current_function) {
// We found an upvalue but it is not at the same level
// Ensure all levels have the upvalue
add_upvalue_in_levels_upto(parser, parser->current_function, symbol->upvalue.function, symbol->upvalue.var);
// TODO Following search could be avoided if above returned the symbol
symbol = search_upvalue_in_function(parser->current_function, varname);
}
}
@ -563,7 +567,7 @@ static struct ast_node *new_symbol_reference(struct parser_state *parser) {
global->symbol_type = SYM_GLOBAL;
global->var.var_name = varname;
global->var.block = NULL;
set_type(global->value_type, RAVI_TANY);
set_type(global->value_type, RAVI_TANY); // Globals are always ANY type
// We don't add globals to any scope so that they are
// always looked up
symbol = global;
@ -1540,9 +1544,10 @@ static struct ast_node *parse_statement(struct parser_state *parser) {
static void parse_statement_list(struct parser_state *parser, struct ast_node_list **list) {
LexState *ls = parser->ls;
while (!block_follow(ls, 1)) {
bool was_return = ls->t.token == TK_RETURN;
struct ast_node *stmt = parse_statement(parser);
if (stmt) add_ast_node(parser->container, list, stmt);
if (ls->t.token == TK_RETURN) { return; /* 'return' must be last statement */ }
if (was_return) break; /* 'return' must be last statement */
}
}
@ -1791,6 +1796,8 @@ static void print_ast_node(membuff_t *buf, struct ast_node *node, int level) {
printf_buf(buf, "%pfunction(\n", level);
print_symbol_list(buf, node->function_expr.args, level + 1, ",");
printf_buf(buf, "%p)\n", level);
printf_buf(buf, "%pupvalues ", level);
print_symbol_list(buf, node->function_expr.upvalues, level + 1, ",");
}
else {
printf_buf(buf, "%pfunction()\n", level);
@ -2181,7 +2188,12 @@ static int build_ast(lua_State *L) {
lua_settop(L, RESERVEDSLOT); /* create reserved slot */
status = build_ast_from_reader(L, generic_reader, NULL, chunkname, mode);
}
return status == 0 ? 1 : 0;
if (status != 0) {
lua_pushnil(L);
lua_insert(L, -2); /* put before error message */
return 2; /* return nil plus error message */
}
return 1;
}
static const char *AST_type = "Ravi.AST";

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