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Added lexical scope support.

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This commit is contained in:
yhirose 2015-09-25 15:20:55 -04:00
parent a0bee1d20b
commit 778b175ab0
2 changed files with 63 additions and 23 deletions
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55
language/culebra/culebra.h
View File

@ -9,14 +9,15 @@ const auto grammar_ = R"(
PROGRAM <- _ STATEMENTS _
STATEMENTS <- (STATEMENT (_sp_ (';' / _nl_) (_ STATEMENT)?)*)?
STATEMENT <- DEBUGGER / RETURN / EXPRESSION
STATEMENT <- DEBUGGER / RETURN / LEXICAL_SCOPE / EXPRESSION
DEBUGGER <- debugger
RETURN <- return (_sp_ !_nl_ EXPRESSION)?
LEXICAL_SCOPE <- BLOCK
EXPRESSION <- ASSIGNMENT / LOGICAL_OR
ASSIGNMENT <- MUTABLE _ PRIMARY (_ (ARGUMENTS / INDEX / DOT))* _ '=' _ EXPRESSION
ASSIGNMENT <- LET _ MUTABLE _ PRIMARY (_ (ARGUMENTS / INDEX / DOT))* _ '=' _ EXPRESSION
LOGICAL_OR <- LOGICAL_AND (_ '||' _ LOGICAL_AND)*
LOGICAL_AND <- CONDITION (_ '&&' _ CONDITION)*
@ -50,6 +51,7 @@ const auto grammar_ = R"(
UNARY_NOT_OPERATOR <- '!'
MULTIPLICATIVE_OPERATOR <- [*/%]
LET <- < ('let' _wd_)? >
MUTABLE <- < ('mut' _wd_)? >
IDENTIFIER <- < IdentInitChar IdentChar* >
@ -558,7 +560,7 @@ struct Interpreter
case "IF"_: return eval_if(ast, env);
case "FUNCTION"_: return eval_function(ast, env);
case "CALL"_: return eval_call(ast, env);
case "BLOCK"_: return eval_block(ast, env);
case "LEXICAL_SCOPE"_: return eval_lexical_scope(ast, env);
case "ASSIGNMENT"_: return eval_assignment(ast, env);
case "LOGICAL_OR"_: return eval_logical_or(ast, env);
case "LOGICAL_AND"_: return eval_logical_and(ast, env);
@ -726,7 +728,12 @@ private:
return val;
}
Value eval_block(const peg::Ast& ast, std::shared_ptr<Environment> env) {
Value eval_lexical_scope(const peg::Ast& ast, std::shared_ptr<Environment> env) {
auto scopeEnv = std::make_shared<Environment>();
scopeEnv->append_outer(env);
for (auto node: ast.nodes) {
eval(*node, scopeEnv);
}
return Value();
}
@ -806,28 +813,30 @@ private:
}
Value eval_assignment(const peg::Ast& ast, std::shared_ptr<Environment> env) {
auto end = ast.nodes.size() - 1;
auto lvaloff = 2;
auto lvalcnt = ast.nodes.size() - 3;
auto mut = ast.nodes[0]->token == "mut";
auto val = eval(*ast.nodes[end], env);
auto let = ast.nodes[0]->token == "let";
auto mut = ast.nodes[1]->token == "mut";
auto rval = eval(*ast.nodes.back(), env);
if (ast.nodes.size() == 3) {
const auto& ident = ast.nodes[1]->token;
if (env->has(ident)) {
env->assign(ident, val);
if (lvalcnt == 1) {
const auto& ident = ast.nodes[lvaloff]->token;
if (!let && env->has(ident)) {
env->assign(ident, rval);
} else if (is_keyword(ident)) {
throw std::runtime_error("left-hand side is invalid variable name.");
} else {
env->initialize(ident, val, mut);
env->initialize(ident, rval, mut);
}
return val;
return rval;
} else {
using peg::operator"" _;
Value lval = eval(*ast.nodes[1], env);
Value lval = eval(*ast.nodes[lvaloff], env);
auto end = ast.nodes.size() - 2;
for (auto i = 2u; i < end; i++) {
auto end = lvaloff + lvalcnt - 1;
for (auto i = lvaloff + 1; i < end; i++) {
const auto& postfix = *ast.nodes[i];
switch (postfix.original_tag) {
@ -845,21 +854,21 @@ private:
const auto& arr = lval.to_array();
auto idx = eval(postfix, env).to_long();
if (0 <= idx && idx < static_cast<long>(arr.values->size())) {
arr.values->at(idx) = val;
arr.values->at(idx) = rval;
} else {
// TODO: error? or set 'undefined'?
throw std::logic_error("index out of range.");
}
return val;
return rval;
}
case "DOT"_: {
auto& obj = lval.to_object();
auto name = postfix.token;
if (obj.has(name)) {
obj.assign(name, val);
obj.assign(name, rval);
} else {
obj.initialize(name, val, mut);
obj.initialize(name, rval, mut);
}
return val;
return rval;
}
default:
throw std::logic_error("invalid internal condition.");
@ -945,7 +954,7 @@ inline std::shared_ptr<peg::Ast> parse(
std::shared_ptr<peg::Ast> ast;
if (parser.parse_n(expr, len, ast, path.c_str())) {
return peg::AstOptimizer(true, { "PARAMETERS", "ARGUMENTS", "OBJECT", "ARRAY", "RETURN" }).optimize(ast);
return peg::AstOptimizer(true, { "PARAMETERS", "ARGUMENTS", "OBJECT", "ARRAY", "RETURN", "LEXICAL_SCOPE" }).optimize(ast);
}
return nullptr;

31
language/culebra/samples/test.cul
View File

@ -190,6 +190,36 @@ test_interpolated_string = fn () {
assert(ret == 'Hello World!')
}
test_lexical_scope = fn () {
a = 0
{
let a = 1;
assert(a == 1)
}
assert(a == 0)
mut b = 0
{
b = 1;
assert(b == 1)
}
assert(b == 1)
c = 0
{
let mut c = 0;
c = 1
assert(c == 1)
}
assert(c == 0)
obj = {
name: 'object'
}
assert(obj.name == 'object')
}
debugger
test_call()
test_return()
@ -204,5 +234,6 @@ debugger
test_sum()
test_fib()
test_interpolated_string()
test_lexical_scope()
return // end