From cd49fe4f9b338242e1e404fd4dbb0a3ebc1c3a12 Mon Sep 17 00:00:00 2001
From: Shea Levy <shea@shealevy.com>
Date: Tue, 31 Dec 2013 23:56:26 +0000
Subject: Don't use any syntactic sugar for dynamic attrs

This doesn't change any functionality but moves some behavior out of the
parser and into the evaluator in order to simplify the code.

Signed-off-by: Shea Levy <shea@shealevy.com>
---
 src/libexpr/eval.cc | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

(limited to 'src/libexpr/eval.cc')

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index cd3edecaa..3d8ee9934 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -129,6 +129,18 @@ string showType(const Value & v)
 }
 
 
+Symbol getName(const AttrName & name, EvalState & state, Env & env) {
+    if (name.symbol.set()) {
+        return name.symbol;
+    } else {
+        Value nameValue;
+        name.expr->eval(state, env, nameValue);
+        state.forceStringNoCtx(nameValue);
+        return state.symbols.create(nameValue.string.s);
+    }
+}
+
+
 EvalState::EvalState()
     : sWith(symbols.create("<with>"))
     , sOutPath(symbols.create("outPath"))
@@ -683,17 +695,18 @@ void ExprSelect::eval(EvalState & state, Env & env, Value & v)
         foreach (AttrPath::const_iterator, i, attrPath) {
             nrLookups++;
             Bindings::iterator j;
+            Symbol name = getName(*i, state, env);
             if (def) {
                 state.forceValue(*vAttrs);
                 if (vAttrs->type != tAttrs ||
-                    (j = vAttrs->attrs->find(*i)) == vAttrs->attrs->end())
+                    (j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
                 {
                     def->eval(state, env, v);
                     return;
                 }
             } else {
                 state.forceAttrs(*vAttrs);
-                if ((j = vAttrs->attrs->find(*i)) == vAttrs->attrs->end())
+                if ((j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
                     throwEvalError("attribute `%1%' missing", showAttrPath(attrPath));
             }
             vAttrs = j->value;
@@ -724,8 +737,9 @@ void ExprOpHasAttr::eval(EvalState & state, Env & env, Value & v)
     foreach (AttrPath::const_iterator, i, attrPath) {
         state.forceValue(*vAttrs);
         Bindings::iterator j;
+        Symbol name = getName(*i, state, env);
         if (vAttrs->type != tAttrs ||
-            (j = vAttrs->attrs->find(*i)) == vAttrs->attrs->end())
+            (j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
         {
             mkBool(v, false);
             return;
-- 
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