From 4f3725b167cc0080c570a814e28c6181ef5c7f52 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 19 Jul 2006 15:36:15 +0000 Subject: * Better error messages (especially wrt types). --- src/libexpr/eval.cc | 64 +++++++++++++++++++++++++++++++---------------------- 1 file changed, 37 insertions(+), 27 deletions(-) (limited to 'src/libexpr/eval.cc') diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 667961cd506a..5315619d4617 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -41,7 +41,7 @@ static Expr substArgs(Expr body, ATermList formals, Expr arg) if (!matchNoDefFormal(*i, name) && !matchDefFormal(*i, name, def)) abort(); /* can't happen */ if (subs[name] == 0) { - if (def == 0) throw Error(format("required function argument `%1%' missing") + if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing") % aterm2String(name)); defsUsed.push_back(name); recAttrs = ATinsert(recAttrs, makeBind(name, def, makeNoPos())); @@ -68,7 +68,7 @@ static Expr substArgs(Expr body, ATermList formals, Expr arg) matchNoDefFormal(*i, name) || matchDefFormal(*i, name, def); subs.remove(name); } - throw Error(format("unexpected function argument `%1%'") + throw TypeError(format("the function does not expect an argument named `%1%'") % aterm2String(subs.begin()->key)); } @@ -133,7 +133,8 @@ string evalString(EvalState & state, Expr e) { e = evalExpr(state, e); ATerm s; - if (!matchStr(e, s)) throw Error("string expected"); + if (!matchStr(e, s)) + throw TypeError(format("value is %1% while a string was expected") % showType(e)); return aterm2String(s); } @@ -142,7 +143,8 @@ Path evalPath(EvalState & state, Expr e) { e = evalExpr(state, e); ATerm s; - if (!matchPath(e, s)) throw Error("path expected"); + if (!matchPath(e, s)) + throw TypeError(format("value is %1% while a path was expected") % showType(e)); return aterm2String(s); } @@ -152,7 +154,7 @@ bool evalBool(EvalState & state, Expr e) e = evalExpr(state, e); if (e == eTrue) return true; else if (e == eFalse) return false; - else throw Error("boolean expected"); + else throw TypeError(format("value is %1% while a boolean was expected") % showType(e)); } @@ -160,7 +162,8 @@ ATermList evalList(EvalState & state, Expr e) { e = evalExpr(state, e); ATermList list; - if (!matchList(e, list)) throw Error("list expected"); + if (!matchList(e, list)) + throw TypeError(format("value is %1% while a list was expected") % showType(e)); return list; } @@ -226,13 +229,13 @@ string coerceToStringWithContext(EvalState & state, Expr a = attrs.get(toATerm("type")); if (a && evalString(state, a) == "derivation") { a = attrs.get(toATerm("outPath")); - if (!a) throw Error("output path missing from derivation"); + if (!a) throw TypeError("output path missing from derivation"); context = ATinsert(context, e); return evalPath(state, a); } } - throw Error("cannot coerce value to string"); + throw TypeError(format("cannot coerce %1% to a string") % showType(e)); } @@ -294,7 +297,7 @@ Expr evalExpr2(EvalState & state, Expr e) if (matchVar(e, name)) { ATerm primOp = state.primOps.get(name); if (!primOp) - throw Error(format("impossible: undefined variable `%1%'") % aterm2String(name)); + throw EvalError(format("impossible: undefined variable `%1%'") % aterm2String(name)); int arity; ATermBlob fun; if (!matchPrimOpDef(primOp, arity, fun)) abort(); @@ -355,7 +358,7 @@ Expr evalExpr2(EvalState & state, Expr e) } } - else throw Error("function or primop expected in function call"); + else throw TypeError("the left-hand side of the function call is neither a function nor a primop (built-in operation)"); } /* Attribute selection. */ @@ -363,7 +366,7 @@ Expr evalExpr2(EvalState & state, Expr e) ATerm pos; string s1 = aterm2String(name); Expr a = queryAttr(evalExpr(state, e1), s1, pos); - if (!a) throw Error(format("attribute `%1%' missing") % s1); + if (!a) throw EvalError(format("attribute `%1%' missing") % s1); try { return evalExpr(state, a); } catch (Error & e) { @@ -451,26 +454,33 @@ Expr evalExpr2(EvalState & state, Expr e) } /* String or path concatenation. */ - if (matchOpPlus(e, e1, e2)) { + ATermList es; + if (matchOpPlus(e, e1, e2) || matchConcatStrings(e, es)) { ATermVector args; - args.push_back(e1); - args.push_back(e2); - return concatStrings(state, args); + if (matchOpPlus(e, e1, e2)) { + args.push_back(e1); + args.push_back(e2); + } else + for (ATermIterator i(es); i; ++i) args.push_back(*i); + + try { + return concatStrings(state, args); + } catch (Error & e) { + e.addPrefix(format("in a string concatenation: ")); + throw; + } } /* List concatenation. */ if (matchOpConcat(e, e1, e2)) { - ATermList l1 = evalList(state, e1); - ATermList l2 = evalList(state, e2); - return makeList(ATconcat(l1, l2)); - } - - /* String concatenation. */ - ATermList es; - if (matchConcatStrings(e, es)) { - ATermVector args; - for (ATermIterator i(es); i; ++i) args.push_back(*i); - return concatStrings(state, args); + try { + ATermList l1 = evalList(state, e1); + ATermList l2 = evalList(state, e2); + return makeList(ATconcat(l1, l2)); + } catch (Error & e) { + e.addPrefix(format("in a list concatenation: ")); + throw; + } } /* Barf. */ @@ -492,7 +502,7 @@ Expr evalExpr(EvalState & state, Expr e) Expr nf = state.normalForms.get(e); if (nf) { if (nf == makeBlackHole()) - throw Error("infinite recursion encountered"); + throw EvalError("infinite recursion encountered"); state.nrCached++; return nf; } -- cgit 1.4.1