* Refactoring: move parseExprFromFile() and parseExprFromString() into

the EvalState class.

src/libexpr/Makefile.am

@@ -6,7 +6,7 @@ libexpr_la_SOURCES = \
  names.cc
 
 pkginclude_HEADERS = \
- nixexpr.hh eval.hh parser.hh lexer-tab.hh parser-tab.hh \
+ nixexpr.hh eval.hh lexer-tab.hh parser-tab.hh \
  get-drvs.hh attr-path.hh value-to-xml.hh common-opts.hh \
  names.hh symbol-table.hh
 

src/libexpr/common-opts.cc

@@ -1,7 +1,6 @@
 #include "common-opts.hh"
 #include "../libmain/shared.hh"
 #include "util.hh"
-#include "parser.hh"
 
 
 namespace nix {
@@ -25,7 +24,7 @@ bool parseOptionArg(const string & arg, Strings::iterator & i,
     autoArgs.push_back(Attr(state.symbols.create(name), v));
 
     if (arg == "--arg")
-        state.mkThunk_(*v, parseExprFromString(state, value, absPath(".")));
+        state.mkThunk_(*v, state.parseExprFromString(value, absPath(".")));
     else
         mkString(*v, value);
 

src/libexpr/eval.cc

@@ -1,5 +1,4 @@
 #include "eval.hh"
-#include "parser.hh"
 #include "hash.hh"
 #include "util.hh"
 #include "store-api.hh"
@@ -427,14 +426,10 @@ void EvalState::evalFile(const Path & path, Value & v)
 {
     startNest(nest, lvlTalkative, format("evaluating file `%1%'") % path);
 
-    Expr * e = parseTrees[path];
-
-    if (!e) {
-        e = parseExprFromFile(*this, path);
-        parseTrees[path] = e;
-    }
+    Expr * e = parseExprFromFile(path);
     
     try {
+        /* !!! Maybe we should cache the evaluation result. */
         eval(e, v);
     } catch (Error & e) {
         addErrorPrefix(e, "while evaluating the file `%1%':\n", path);

src/libexpr/eval.hh

@@ -218,6 +218,13 @@ public:
     EvalState();
     ~EvalState();
 
+    /* Parse a Nix expression from the specified file.  If `path'
+       refers to a directory, then "/default.nix" is appended. */
+    Expr * parseExprFromFile(Path path);
+
+    /* Parse a Nix expression from the specified string. */
+    Expr * parseExprFromString(const string & s, const Path & basePath);
+    
     /* Evaluate an expression read from the given file to normal
        form. */
     void evalFile(const Path & path, Value & v);
@@ -296,6 +303,9 @@ private:
     friend class ExprAttrs;
     friend class ExprLet;
 
+    Expr * parse(const char * text,
+        const Path & path, const Path & basePath);
+
 public:
     
     /* Do a deep equality test between two values.  That is, list

src/libexpr/parser.hh

@@ -1,21 +0,0 @@
-#ifndef __PARSER_H
-#define __PARSER_H
-
-#include "eval.hh"
-
-
-namespace nix {
-
-
-/* Parse a Nix expression from the specified file.  If `path' refers
-   to a directory, then "/default.nix" is appended. */
-Expr * parseExprFromFile(EvalState & state, Path path);
-
-/* Parse a Nix expression from the specified string. */
-Expr * parseExprFromString(EvalState & state, const string & s, const Path & basePath);
-
-
-}
-
-
-#endif /* !__PARSER_H */

src/libexpr/parser.y

@@ -450,11 +450,11 @@ formal
 namespace nix {
       
 
-static Expr * parse(EvalState & state, const char * text,
+Expr * EvalState::parse(const char * text,
     const Path & path, const Path & basePath)
 {
     yyscan_t scanner;
-    ParseData data(state.symbols);
+    ParseData data(symbols);
     data.basePath = basePath;
     data.path = path;
 
@@ -466,7 +466,7 @@ static Expr * parse(EvalState & state, const char * text,
     if (res) throw ParseError(data.error);
 
     try {
-        data.result->bindVars(state.staticBaseEnv);
+        data.result->bindVars(staticBaseEnv);
     } catch (Error & e) {
         throw ParseError(format("%1%, in `%2%'") % e.msg() % path);
     }
@@ -475,7 +475,7 @@ static Expr * parse(EvalState & state, const char * text,
 }
 
 
-Expr * parseExprFromFile(EvalState & state, Path path)
+Expr * EvalState::parseExprFromFile(Path path)
 {
     assert(path[0] == '/');
 
@@ -493,15 +493,21 @@ Expr * parseExprFromFile(EvalState & state, Path path)
     if (S_ISDIR(st.st_mode))
         path = canonPath(path + "/default.nix");
 
-    /* Read and parse the input file. */
-    return parse(state, readFile(path).c_str(), path, dirOf(path));
+    /* Read and parse the input file, unless it's already in the parse
+       tree cache. */
+    Expr * e = parseTrees[path];
+    if (!e) {
+        e = parse(readFile(path).c_str(), path, dirOf(path));
+        parseTrees[path] = e;
+    }
+
+    return e;
 }
 
 
-Expr * parseExprFromString(EvalState & state,
-    const string & s, const Path & basePath)
+Expr * EvalState::parseExprFromString(const string & s, const Path & basePath)
 {
-    return parse(state, s.c_str(), "(string)", basePath);
+    return parse(s.c_str(), "(string)", basePath);
 }
 
  

src/libexpr/primops.cc

@@ -5,7 +5,6 @@
 #include "util.hh"
 #include "archive.hh"
 #include "value-to-xml.hh"
-#include "parser.hh"
 #include "names.hh"
 
 #include <sys/types.h>
@@ -1059,7 +1058,7 @@ void EvalState::createBaseEnv()
     /* Add a wrapper around the derivation primop that computes the
        `drvPath' and `outPath' attributes lazily. */
     string s = "attrs: let res = derivationStrict attrs; in attrs // { drvPath = res.drvPath; outPath = res.outPath; type = \"derivation\"; }";
-    mkThunk_(v, parseExprFromString(*this, s, "/"));
+    mkThunk_(v, parseExprFromString(s, "/"));
     addConstant("derivation", v);
 
     // Paths