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Show the exact position of undefined variables

Browse source 
In particular, undefined variable errors in a "with" previously didn't
show *any* position information, so this should help a lot in those
cases.
This commit is contained in:
Eelco Dolstra 2013-10-08 14:40:51 +02:00
parent a5e0f64db3
commit 6b47de580f
4 changed files with 18 additions and 21 deletions
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2
src/libexpr/eval.cc
View file

@ -315,7 +315,7 @@ inline Value * EvalState::lookupVar(Env * env, const ExprVar & var, bool noEval)
return j->value;
}
if (!env->prevWith)
throwEvalError("undefined variable `%1%'", var.name);
throw EvalError(format("undefined variable `%1%' at %2%") % var.name % var.pos);
for (unsigned int l = env->prevWith; l; --l, env = env->up) ;
}
}

2
src/libexpr/nixexpr.cc
View file

@ -198,7 +198,7 @@ void ExprVar::bindVars(const StaticEnv & env)
/* Otherwise, the variable must be obtained from the nearest
enclosing `with'. If there is no `with', then we can issue an
"undefined variable" error now. */
if (withLevel == -1) throw EvalError(format("undefined variable `%1%'") % name);
if (withLevel == -1) throw ParseError(format("undefined variable `%1%' at %2%") % name % pos);
fromWith = true;
this->level = withLevel;

3
src/libexpr/nixexpr.hh
View file

@ -109,6 +109,7 @@ struct ExprPath : Expr
struct ExprVar : Expr
{
Pos pos;
Symbol name;
/* Whether the variable comes from an environment (e.g. a rec, let
@ -124,7 +125,7 @@ struct ExprVar : Expr
unsigned int level;
unsigned int displ;
ExprVar(const Symbol & name) : name(name) { };
ExprVar(const Pos & pos, const Symbol & name) : pos(pos), name(name) { };
COMMON_METHODS
Value * maybeThunk(EvalState & state, Env & env);
};

32
src/libexpr/parser.y
View file

@ -310,13 +310,13 @@ expr_if
expr_op
: '!' expr_op %prec NOT { $$ = new ExprOpNot($2); }
| '-' expr_op %prec NEGATE { $$ = new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__sub")), new ExprInt(0)), $2); }
| '-' expr_op %prec NEGATE { $$ = new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__sub")), new ExprInt(0)), $2); }
| expr_op EQ expr_op { $$ = new ExprOpEq($1, $3); }
| expr_op NEQ expr_op { $$ = new ExprOpNEq($1, $3); }
| expr_op '<' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__lessThan")), $1), $3); }
| expr_op LEQ expr_op { $$ = new ExprOpNot(new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__lessThan")), $3), $1)); }
| expr_op '>' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__lessThan")), $3), $1); }
| expr_op GEQ expr_op { $$ = new ExprOpNot(new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__lessThan")), $1), $3)); }
| expr_op '<' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__lessThan")), $1), $3); }
| expr_op LEQ expr_op { $$ = new ExprOpNot(new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__lessThan")), $3), $1)); }
| expr_op '>' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__lessThan")), $3), $1); }
| expr_op GEQ expr_op { $$ = new ExprOpNot(new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__lessThan")), $1), $3)); }
| expr_op AND expr_op { $$ = new ExprOpAnd($1, $3); }
| expr_op OR expr_op { $$ = new ExprOpOr($1, $3); }
| expr_op IMPL expr_op { $$ = new ExprOpImpl($1, $3); }
@ -328,9 +328,9 @@ expr_op
l->push_back($3);
$$ = new ExprConcatStrings(false, l);
}
| expr_op '-' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__sub")), $1), $3); }
| expr_op '*' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__mul")), $1), $3); }
| expr_op '/' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(data->symbols.create("__div")), $1), $3); }
| expr_op '-' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__sub")), $1), $3); }
| expr_op '*' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__mul")), $1), $3); }
| expr_op '/' expr_op { $$ = new ExprApp(new ExprApp(new ExprVar(noPos, data->symbols.create("__div")), $1), $3); }
| expr_op CONCAT expr_op { $$ = new ExprOpConcatLists($1, $3); }
| expr_app
;
@ -349,12 +349,12 @@ expr_select
| /* Backwards compatibility: because Nixpkgs has a rarely used
function named ‘or’, allow stuff like ‘map or [...]’. */
expr_simple OR_KW
{ $$ = new ExprApp($1, new ExprVar(data->symbols.create("or"))); }
{ $$ = new ExprApp($1, new ExprVar(CUR_POS, data->symbols.create("or"))); }
| expr_simple { $$ = $1; }
;
expr_simple
: ID { $$ = new ExprVar(data->symbols.create($1)); }
: ID { $$ = new ExprVar(CUR_POS, data->symbols.create($1)); }
| INT { $$ = new ExprInt($1); }
| '"' string_parts '"' {
/* For efficiency, and to simplify parse trees a bit. */
@ -372,10 +372,10 @@ expr_simple
/* The file wasn't found in the search path. However, we can't
throw an error here, because the expression might never be
evaluated. So return an expression that lazily calls
‘abort’. */
‘throw’. */
$$ = path2 == ""
? (Expr * ) new ExprApp(
new ExprVar(data->symbols.create("throw")),
new ExprVar(noPos, data->symbols.create("throw")),
new ExprString(data->symbols.create(
(format("file `%1%' was not found in the Nix search path (add it using $NIX_PATH or -I)") % path).str())))
: (Expr * ) new ExprPath(path2);
@ -413,7 +413,7 @@ binds
if ($$->attrs.find(*i) != $$->attrs.end())
dupAttr(*i, makeCurPos(@3, data), $$->attrs[*i].pos);
Pos pos = makeCurPos(@3, data);
$$->attrs[*i] = ExprAttrs::AttrDef(new ExprVar(*i), pos, true);
$$->attrs[*i] = ExprAttrs::AttrDef(new ExprVar(CUR_POS, *i), pos, true);
}
}
| binds INHERIT '(' expr ')' attrs ';'
@ -495,11 +495,7 @@ Expr * EvalState::parse(const char * text,
if (res) throw ParseError(data.error);
try {
data.result->bindVars(staticEnv);
} catch (Error & e) {
throw ParseError(format("%1%, in `%2%'") % e.msg() % path);
}
data.result->bindVars(staticEnv);
return data.result;
}