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Fixed 'uninitialized variable' problem in PL/0 interpreter

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This commit is contained in:
yhirose 2017-08-03 22:56:12 -04:00
parent 41e3360483
commit bb0c7c4522
1 changed files with 6 additions and 4 deletions
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10
language/pl0/pl0.cc
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@ -206,14 +206,17 @@ struct Environment
Environment(shared_ptr<SymbolScope> scope, shared_ptr<Environment> outer) Environment(shared_ptr<SymbolScope> scope, shared_ptr<Environment> outer)
: scope(scope), outer(outer) {} : scope(scope), outer(outer) {}
int get_value(const string& ident) const { int get_value(const shared_ptr<AstPL0> ast, const string& ident) const {
auto it = scope->constants.find(ident); auto it = scope->constants.find(ident);
if (it != scope->constants.end()) { if (it != scope->constants.end()) {
return it->second; return it->second;
} else if (scope->variables.count(ident)) { } else if (scope->variables.count(ident)) {
if (variables.find(ident) == variables.end()) {
throw_runtime_error(ast, "uninitialized variable '" + ident + "'...");
}
return variables.at(ident); return variables.at(ident);
} }
return outer->get_value(ident); return outer->get_value(ast, ident);
} }
void set_variable(const string& ident, int val) { void set_variable(const string& ident, int val) {
@ -395,7 +398,7 @@ private:
} }
static int eval_ident(const shared_ptr<AstPL0> ast, shared_ptr<Environment> env) { static int eval_ident(const shared_ptr<AstPL0> ast, shared_ptr<Environment> env) {
return env->get_value(ast->token); return env->get_value(ast, ast->token);
} }
static int eval_number(const shared_ptr<AstPL0> ast, shared_ptr<Environment> env) { static int eval_number(const shared_ptr<AstPL0> ast, shared_ptr<Environment> env) {
@ -453,4 +456,3 @@ int main(int argc, const char** argv)
} }
// vim: et ts=4 sw=4 cin cino={1s ff=unix // vim: et ts=4 sw=4 cin cino={1s ff=unix