From 38f18aa6d418515e42b688fa9b3e4f3ab61bb89e Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Wed, 23 Aug 2006 15:46:00 +0000
Subject: [PATCH] * New primop: abort "error message".

---
 src/libexpr/eval.cc            | 4 ++--
 src/libexpr/nixexpr.hh         | 1 +
 src/libexpr/primops.cc         | 8 ++++++++
 tests/lang/eval-fail-abort.nix | 1 +
 4 files changed, 12 insertions(+), 2 deletions(-)
 create mode 100644 tests/lang/eval-fail-abort.nix

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index ce38e2ab92..c4f5d7f5d6 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -515,7 +515,7 @@ Expr evalExpr2(EvalState & state, Expr e)
         try {
             return concatStrings(state, args);
         } catch (Error & e) {
-            e.addPrefix(format("in a string concatenation: "));
+            e.addPrefix(format("in a string concatenation:\n"));
             throw;
         }
     }
@@ -527,7 +527,7 @@ Expr evalExpr2(EvalState & state, Expr e)
             ATermList l2 = evalList(state, e2);
             return makeList(ATconcat(l1, l2));
         } catch (Error & e) {
-            e.addPrefix(format("in a list concatenation: "));
+            e.addPrefix(format("in a list concatenation:\n"));
             throw;
         }
     }
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index 28ac35e604..3eb4d4cb2b 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -11,6 +11,7 @@
 
 MakeError(EvalError, Error)
 MakeError(AssertionError, EvalError)
+MakeError(Abort, EvalError)
 MakeError(TypeError, EvalError)
 
 
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index bc4db2d813..2bc5459d13 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -629,6 +629,13 @@ static Expr primDependencyClosure(EvalState & state, const ATermVector & args)
 }
 
 
+static Expr primAbort(EvalState & state, const ATermVector & args)
+{
+    throw Abort(format("evaluation aborted with the following error message: %1%") %
+        evalString(state, args[0]));
+}
+
+
 /* Apply a function to every element of a list. */
 static Expr primMap(EvalState & state, const ATermVector & args)
 {
@@ -700,6 +707,7 @@ void EvalState::addPrimOps()
     addPrimOp("toString", 1, primToString);
     addPrimOp("isNull", 1, primIsNull);
     addPrimOp("dependencyClosure", 1, primDependencyClosure);
+    addPrimOp("abort", 1, primAbort);
 
     addPrimOp("map", 2, primMap);
     addPrimOp("removeAttrs", 2, primRemoveAttrs);
diff --git a/tests/lang/eval-fail-abort.nix b/tests/lang/eval-fail-abort.nix
new file mode 100644
index 0000000000..75c51bceb5
--- /dev/null
+++ b/tests/lang/eval-fail-abort.nix
@@ -0,0 +1 @@
+if true then abort "this should fail" else 1