1 files changed, 266 insertions, 0 deletions
diff --git a/src/fix.cc b/src/fix.cc
new file mode 100644
index 000000000000..cb42aca6b773
--- /dev/null
+++ b/src/fix.cc
@@ -0,0 +1,266 @@
+#include <map>
+#include <iostream>
+
+#include "globals.hh"
+#include "eval.hh"
+#include "values.hh"
+#include "shared.hh"
+
+
+typedef ATerm Expr;
+
+
+static Expr evalFile(string fileName);
+
+
+static bool isFState(Expr e, string & path)
+{
+    char * s1, * s2, * s3;
+    Expr e1, e2;
+    if (ATmatch(e, "Path(<str>, <term>, [<list>])", &s1, &e1, &e2)) {
+        path = s1;
+        return true;
+    }
+    else if (ATmatch(e, "Derive(<str>, <str>, [<list>], <str>, [<list>])",
+                   &s1, &s2, &e1, &s3, &e2))
+    {
+        path = s3;
+        return true;
+    }
+    else if (ATmatch(e, "Include(<str>)", &s1))
+    {
+        string fn = queryFromStore(parseHash(s1));
+        return isFState(evalFile(fn), path);
+    }
+    else return false;
+}
+
+
+static Expr substExpr(string x, Expr rep, Expr e)
+{
+    char * s;
+    Expr e2;
+
+    if (ATmatch(e, "Var(<str>)", &s))
+        if (x == s)
+            return rep;
+        else
+            return e;
+
+    if (ATmatch(e, "Lam(<str>, <term>)", &s, &e2))
+        if (x == s)
+            return e;
+    /* !!! unfair substitutions */
+
+    /* Generically substitute in subterms. */
+
+    if (ATgetType(e) == AT_APPL) {
+        AFun fun = ATgetAFun(e);
+        int arity = ATgetArity(fun);
+        ATermList args = ATempty;
+
+        for (int i = arity - 1; i >= 0; i--)
+            args = ATinsert(args, substExpr(x, rep, ATgetArgument(e, i)));
+        
+        return (ATerm) ATmakeApplList(fun, args);
+    }
+
+    if (ATgetType(e) == AT_LIST) {
+        ATermList in = (ATermList) e;
+        ATermList out = ATempty;
+
+        while (!ATisEmpty(in)) {
+            out = ATinsert(out, substExpr(x, rep, ATgetFirst(in)));
+            in = ATgetNext(in);
+        }
+
+        return (ATerm) ATreverse(out);
+    }
+
+    throw badTerm("do not know how to substitute", e);
+}
+
+
+static Expr substExprMany(ATermList formals, ATermList args, Expr body)
+{
+    char * s;
+    Expr e;
+
+    /* !!! check args against formals */
+
+    while (!ATisEmpty(args)) {
+        ATerm tup = ATgetFirst(args);
+        if (!ATmatch(tup, "(<str>, <term>)", &s, &e))
+            throw badTerm("expected an argument tuple", tup);
+
+        body = substExpr(s, e, body);
+
+        args = ATgetNext(args);
+    }
+    
+    return body;
+}
+
+
+static Expr evalExpr(Expr e)
+{
+    char * s1;
+    Expr e1, e2, e3, e4;
+    ATermList bnds;
+
+    /* Normal forms. */
+    if (ATmatch(e, "<str>", &s1) ||
+        ATmatch(e, "Function([<list>], <term>)", &e1, &e2))
+        return e;
+
+    string dummy;
+    if (isFState(e, dummy)) return e;
+
+    /* Application. */
+    if (ATmatch(e, "App(<term>, [<list>])", &e1, &e2)) {
+        e1 = evalExpr(e1);
+        if (!ATmatch(e1, "Function([<list>], <term>)", &e3, &e4))
+            throw badTerm("expecting a function", e1);
+        return evalExpr(substExprMany((ATermList) e3, (ATermList) e2, e4));
+    }
+
+    /* Fix inclusion. */
+    if (ATmatch(e, "IncludeFix(<str>)", &s1)) {
+        string fileName(s1);
+        return evalFile(s1);
+    }
+
+    /* Relative files. */
+    if (ATmatch(e, "Relative(<str>)", &s1)) {
+        string srcPath = s1;
+        string dstPath;
+        Hash hash;
+        addToStore(srcPath, dstPath, hash);
+        return ATmake("Path(<str>, Hash(<str>), [])",
+            dstPath.c_str(), ((string) hash).c_str());
+    }
+
+    /* Packages are transformed into Derive fstate expressions. */
+    if (ATmatch(e, "Package([<list>])", &bnds)) {
+
+        /* Evaluate the bindings and put them in a map. */
+        map<string, ATerm> bndMap;
+        bndMap["platform"] = ATmake("<str>", SYSTEM);
+        while (!ATisEmpty(bnds)) {
+            ATerm bnd = ATgetFirst(bnds);
+            if (!ATmatch(bnd, "(<str>, <term>)", &s1, &e1))
+                throw badTerm("binding expected", bnd);
+            bndMap[s1] = evalExpr(e1);
+            bnds = ATgetNext(bnds);
+        }
+
+        /* Gather information for building the Derive expression. */
+        ATermList ins = ATempty, env = ATempty;
+        string builder, id;
+        bnds = ATempty;
+
+        for (map<string, ATerm>::iterator it = bndMap.begin();
+             it != bndMap.end(); it++)
+        {
+            string key = it->first;
+            ATerm value = it->second;
+
+            string path;
+            if (isFState(value, path)) {
+                ins = ATinsert(ins, value);
+                env = ATinsert(env, ATmake("(<str>, <str>)",
+                    key.c_str(), path.c_str()));
+                if (key == "build") builder = path;
+            }
+            else if (ATmatch(value, "<str>", &s1)) {
+                if (key == "id") id = s1;
+                env = ATinsert(env, 
+                    ATmake("(<str>, <str>)", key.c_str(), s1));
+            }
+            else throw badTerm("invalid package argument", value);
+
+            bnds = ATinsert(bnds, 
+                ATmake("(<str>, <term>)", key.c_str(), value));
+        }
+
+        /* Hash the normal form to produce a unique but deterministic
+           path name for this package. */
+        ATerm nf = ATmake("Package(<term>)", ATreverse(bnds));
+        debug(printTerm(nf));
+        Hash hash = hashTerm(nf);
+
+        if (builder == "")
+            throw badTerm("no builder specified", nf);
+        
+        if (id == "")
+            throw badTerm("no package identifier specified", nf);
+        
+        string out = nixStore + "/" + ((string) hash).c_str() + "-" + id;
+
+        env = ATinsert(env, ATmake("(<str>, <str>)", "out", out.c_str()));
+
+        /* Construct the result. */
+        e = ATmake("Derive(<str>, <str>, <term>, <str>, <term>)",
+            SYSTEM, builder.c_str(), ins, out.c_str(), env);
+        debug(printTerm(e));
+
+        /* Write the resulting term into the Nix store directory. */
+        Hash eHash = writeTerm(e);
+
+        return ATmake("Include(<str>)", ((string) eHash).c_str());
+    }
+
+    /* Barf. */
+    throw badTerm("invalid expression", e);
+}
+
+
+static Strings searchPath;
+
+
+static Expr evalFile(string fileName)
+{
+    Expr e = ATreadFromNamedFile(fileName.c_str());
+    if (!e) throw Error(format("cannot read aterm `%1%'") % fileName);
+    return evalExpr(e);
+}
+
+
+void run(Strings args)
+{
+    Strings files;
+
+    searchPath.push_back(".");
+    
+    for (Strings::iterator it = args.begin();
+         it != args.end(); )
+    {
+        string arg = *it++;
+
+        if (arg == "--includedir" || arg == "-I") {
+            if (it == args.end())
+                throw UsageError(format("argument required in `%1%'") % arg);
+            searchPath.push_back(*it++);
+        }
+        else if (arg[0] == '-')
+            throw UsageError(format("unknown flag `%1%`") % arg);
+        else
+            files.push_back(arg);
+    }
+
+    if (files.empty()) throw UsageError("no files specified");
+
+    for (Strings::iterator it = files.begin();
+         it != files.end(); it++)
+    {
+        Expr e = evalFile(*it);
+        char * s;
+        if (ATmatch(e, "Include(<str>)", &s)) {
+            cout << format("%1%\n") % s;
+        } 
+        else throw badTerm("top level is not a package", e);
+    }
+}
+
+
+string programId = "fix";