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* Added syntactic sugar to the construction of attribute sets to

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`inherit' variables from the surrounding lexical scope.

  E.g.,

    {stdenv, libfoo}: derivation {
      builder = ./bla;
      inherit stdenv libfoo;
      xyzzy = 1;
    }

  is equivalent to

    {stdenv, libfoo}: derivation {
      builder = ./bla;
      stdenv = stdenv;
      libfoo = libfoo;
      xyzzy = 1;
    }

  Note that for mutually recursive attribute set definitions (`rec
  {...}'), this also works, that is, `rec {inherit x;}' is equivalent
  to `let {fresh = x; body = rec {x = fresh;};}', *not*
  `rec {x = x}'.
This commit is contained in:
Eelco Dolstra 2004-02-02 21:39:33 +00:00
parent d9f30fe7c7
commit 1c9c0a5a46
6 changed files with 78 additions and 41 deletions
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56
src/libexpr/parser.cc
View file

@ -17,32 +17,52 @@ struct ParseData
string error;
};
extern "C" {
#include "parser-tab.h"
#include "lexer-tab.h"
/* Callbacks for getting from C to C++. Due to a (small) bug in the
GLR code of Bison we cannot currently compile the parser as C++
code. */
void setParseResult(ParseData * data, ATerm t)
{
data->result = t;
}
/* Callbacks for getting from C to C++. Due to a (small) bug in the
GLR code of Bison we cannot currently compile the parser as C++
code. */
ATerm absParsedPath(ParseData * data, ATerm t)
{
return string2ATerm(absPath(aterm2String(t), data->basePath).c_str());
}
void setParseResult(ParseData * data, ATerm t)
{
data->result = t;
}
ATerm absParsedPath(ParseData * data, ATerm t)
{
return string2ATerm(absPath(aterm2String(t), data->basePath).c_str());
}
void parseError(ParseData * data, char * error, int line, int column)
{
data->error = (format("%1%, at line %2%, column %3%, of %4%")
% error % line % column % data->location).str();
}
void parseError(ParseData * data, char * error, int line, int column)
{
data->error = (format("%1%, at line %2%, column %3%, of %4%")
% error % line % column % data->location).str();
}
int yyparse(yyscan_t scanner, ParseData * data);
ATerm fixAttrs(int recursive, ATermList as)
{
ATMatcher m;
ATermList bs = ATempty, cs = ATempty;
ATermList * is = recursive ? &cs : &bs;
for (ATermIterator i(as); i; ++i) {
ATermList names;
if (atMatch(m, *i) >> "Inherit" >> names)
for (ATermIterator j(names); j; ++j)
*is = ATinsert(*is,
ATmake("Bind(<term>, Var(<term>))", *j, *j));
else bs = ATinsert(bs, *i);
}
if (recursive)
return ATmake("Rec(<term>, <term>)", bs, cs);
else
return ATmake("Attrs(<term>)", bs);
}
int yyparse(yyscan_t scanner, ParseData * data);
}