forked from lix-project/lix
a64bbe049e
attributes of the rec are in scope of `e'. This is useful in
expressions such as
rec {
lib = import ./lib;
inherit (lib) concatStrings;
}
It does change the semantics of expressions such as
let x = {y = 1;}; in rec { x = {y = 2;}; inherit (x) y; }.y
This now returns 2 instead of 1. However, no code in Nixpkgs or
NixOS seems to rely on the old behaviour.
563 lines
15 KiB
Plaintext
563 lines
15 KiB
Plaintext
%glr-parser
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%pure-parser
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%locations
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%error-verbose
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%defines
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/* %no-lines */
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%parse-param { yyscan_t scanner }
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%parse-param { ParseData * data }
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%lex-param { yyscan_t scanner }
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%{
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/* Newer versions of Bison copy the declarations below to
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parser-tab.hh, which sucks bigtime since lexer.l doesn't want that
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stuff. So allow it to be excluded. */
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#ifndef BISON_HEADER_HACK
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#define BISON_HEADER_HACK
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "aterm.hh"
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#include "util.hh"
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#include "parser-tab.hh"
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#include "lexer-tab.hh"
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#define YYSTYPE YYSTYPE // workaround a bug in Bison 2.4
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#include "nixexpr.hh"
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#include "nixexpr-ast.hh"
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using namespace nix;
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namespace nix {
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struct ParseData
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{
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Expr result;
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Path basePath;
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Path path;
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string error;
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};
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static string showAttrPath(ATermList attrPath)
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{
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string s;
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for (ATermIterator i(attrPath); i; ++i) {
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if (!s.empty()) s += '.';
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s += aterm2String(*i);
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}
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return s;
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}
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struct Tree
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{
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Expr leaf; ATerm pos; bool recursive;
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typedef std::map<ATerm, Tree> Children;
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Children children;
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Tree() { leaf = 0; recursive = true; }
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};
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static ATermList buildAttrs(const Tree & t, ATermList & nonrec)
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{
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ATermList res = ATempty;
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for (Tree::Children::const_reverse_iterator i = t.children.rbegin();
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i != t.children.rend(); ++i)
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if (!i->second.recursive)
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nonrec = ATinsert(nonrec, makeBind(i->first, i->second.leaf, i->second.pos));
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else
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res = ATinsert(res, i->second.leaf
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? makeBind(i->first, i->second.leaf, i->second.pos)
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: makeBind(i->first, makeAttrs(buildAttrs(i->second, nonrec)), makeNoPos()));
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return res;
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}
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static Expr fixAttrs(bool recursive, ATermList as)
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{
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Tree attrs;
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for (ATermIterator i(as); i; ++i) {
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ATermList names, attrPath; Expr src, e; ATerm name, pos;
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if (matchInherit(*i, src, names, pos)) {
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bool fromScope = matchScope(src);
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for (ATermIterator j(names); j; ++j) {
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if (attrs.children.find(*j) != attrs.children.end())
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throw ParseError(format("duplicate definition of attribute `%1%' at %2%")
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% showAttrPath(ATmakeList1(*j)) % showPos(pos));
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Tree & t(attrs.children[*j]);
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t.leaf = fromScope ? makeVar(*j) : makeSelect(src, *j);
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t.pos = pos;
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if (recursive && fromScope) t.recursive = false;
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}
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}
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else if (matchBindAttrPath(*i, attrPath, e, pos)) {
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Tree * t(&attrs);
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for (ATermIterator j(attrPath); j; ) {
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name = *j; ++j;
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if (t->leaf) throw ParseError(format("attribute set containing `%1%' at %2% already defined at %3%")
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% showAttrPath(attrPath) % showPos(pos) % showPos (t->pos));
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t = &(t->children[name]);
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}
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if (t->leaf)
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throw ParseError(format("duplicate definition of attribute `%1%' at %2% and %3%")
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% showAttrPath(attrPath) % showPos(pos) % showPos (t->pos));
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if (!t->children.empty())
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throw ParseError(format("duplicate definition of attribute `%1%' at %2%")
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% showAttrPath(attrPath) % showPos(pos));
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t->leaf = e; t->pos = pos;
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}
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else abort(); /* can't happen */
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}
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ATermList nonrec = ATempty;
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ATermList rec = buildAttrs(attrs, nonrec);
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return recursive ? makeRec(rec, nonrec) : makeAttrs(rec);
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}
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static void checkPatternVars(ATerm pos, ATermMap & map, Pattern pat)
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{
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ATerm name;
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ATermList formals;
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Pattern pat1, pat2;
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ATermBool ellipsis;
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if (matchVarPat(pat, name)) {
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if (map.get(name))
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throw ParseError(format("duplicate formal function argument `%1%' at %2%")
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% aterm2String(name) % showPos(pos));
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map.set(name, name);
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}
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else if (matchAttrsPat(pat, formals, ellipsis)) {
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for (ATermIterator i(formals); i; ++i) {
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ATerm d1;
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if (!matchFormal(*i, name, d1)) abort();
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if (map.get(name))
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throw ParseError(format("duplicate formal function argument `%1%' at %2%")
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% aterm2String(name) % showPos(pos));
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map.set(name, name);
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}
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}
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else if (matchAtPat(pat, pat1, pat2)) {
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checkPatternVars(pos, map, pat1);
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checkPatternVars(pos, map, pat2);
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}
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else abort();
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}
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static void checkPatternVars(ATerm pos, Pattern pat)
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{
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ATermMap map;
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checkPatternVars(pos, map, pat);
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}
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static Expr stripIndentation(ATermList es)
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{
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if (es == ATempty) return makeStr("");
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/* Figure out the minimum indentation. Note that by design
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whitespace-only final lines are not taken into account. (So
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the " " in "\n ''" is ignored, but the " " in "\n foo''" is.) */
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bool atStartOfLine = true; /* = seen only whitespace in the current line */
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unsigned int minIndent = 1000000;
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unsigned int curIndent = 0;
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ATerm e;
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for (ATermIterator i(es); i; ++i) {
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if (!matchIndStr(*i, e)) {
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/* Anti-quotations end the current start-of-line whitespace. */
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if (atStartOfLine) {
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atStartOfLine = false;
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if (curIndent < minIndent) minIndent = curIndent;
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}
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continue;
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}
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string s = aterm2String(e);
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for (unsigned int j = 0; j < s.size(); ++j) {
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if (atStartOfLine) {
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if (s[j] == ' ')
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curIndent++;
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else if (s[j] == '\n') {
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/* Empty line, doesn't influence minimum
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indentation. */
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curIndent = 0;
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} else {
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atStartOfLine = false;
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if (curIndent < minIndent) minIndent = curIndent;
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}
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} else if (s[j] == '\n') {
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atStartOfLine = true;
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curIndent = 0;
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}
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}
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}
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/* Strip spaces from each line. */
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ATermList es2 = ATempty;
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atStartOfLine = true;
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unsigned int curDropped = 0;
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unsigned int n = ATgetLength(es);
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for (ATermIterator i(es); i; ++i, --n) {
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if (!matchIndStr(*i, e)) {
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atStartOfLine = false;
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curDropped = 0;
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es2 = ATinsert(es2, *i);
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continue;
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}
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string s = aterm2String(e);
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string s2;
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for (unsigned int j = 0; j < s.size(); ++j) {
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if (atStartOfLine) {
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if (s[j] == ' ') {
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if (curDropped++ >= minIndent)
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s2 += s[j];
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}
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else if (s[j] == '\n') {
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curDropped = 0;
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s2 += s[j];
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} else {
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atStartOfLine = false;
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curDropped = 0;
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s2 += s[j];
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}
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} else {
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s2 += s[j];
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if (s[j] == '\n') atStartOfLine = true;
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}
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}
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/* Remove the last line if it is empty and consists only of
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spaces. */
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if (n == 1) {
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string::size_type p = s2.find_last_of('\n');
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if (p != string::npos && s2.find_first_not_of(' ', p + 1) == string::npos)
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s2 = string(s2, 0, p + 1);
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}
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es2 = ATinsert(es2, makeStr(s2));
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}
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return makeConcatStrings(ATreverse(es2));
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}
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void backToString(yyscan_t scanner);
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void backToIndString(yyscan_t scanner);
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static Pos makeCurPos(YYLTYPE * loc, ParseData * data)
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{
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return makePos(toATerm(data->path),
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loc->first_line, loc->first_column);
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}
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#define CUR_POS makeCurPos(yylocp, data)
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}
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void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * error)
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{
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data->error = (format("%1%, at `%2%':%3%:%4%")
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% error % data->path % loc->first_line % loc->first_column).str();
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}
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/* Make sure that the parse stack is scanned by the ATerm garbage
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collector. */
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static void * mallocAndProtect(size_t size)
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{
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void * p = malloc(size);
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if (p) ATprotectMemory(p, size);
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return p;
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}
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static void freeAndUnprotect(void * p)
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{
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ATunprotectMemory(p);
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free(p);
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}
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#define YYMALLOC mallocAndProtect
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#define YYFREE freeAndUnprotect
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#endif
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%}
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%union {
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ATerm t;
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ATermList ts;
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struct {
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ATermList formals;
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bool ellipsis;
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} formals;
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}
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%type <t> start expr expr_function expr_if expr_op
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%type <t> expr_app expr_select expr_simple bind inheritsrc formal
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%type <t> pattern pattern2
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%type <ts> binds ids attrpath expr_list string_parts ind_string_parts
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%type <formals> formals
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%token <t> ID INT STR IND_STR PATH URI
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%token IF THEN ELSE ASSERT WITH LET IN REC INHERIT EQ NEQ AND OR IMPL
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%token DOLLAR_CURLY /* == ${ */
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%token IND_STRING_OPEN IND_STRING_CLOSE
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%token ELLIPSIS
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%nonassoc IMPL
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%left OR
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%left AND
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%nonassoc EQ NEQ
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%right UPDATE
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%left NEG
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%left '+'
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%right CONCAT
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%nonassoc '?'
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%nonassoc '~'
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%%
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start: expr { data->result = $1; };
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expr: expr_function;
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expr_function
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: pattern ':' expr_function
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{ checkPatternVars(CUR_POS, $1); $$ = makeFunction($1, $3, CUR_POS); }
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| ASSERT expr ';' expr_function
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{ $$ = makeAssert($2, $4, CUR_POS); }
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| WITH expr ';' expr_function
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{ $$ = makeWith($2, $4, CUR_POS); }
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| LET binds IN expr_function
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{ $$ = makeSelect(fixAttrs(true, ATinsert($2, makeBindAttrPath(ATmakeList1(toATerm("<let-body>")), $4, CUR_POS))), toATerm("<let-body>")); }
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| expr_if
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;
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expr_if
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: IF expr THEN expr ELSE expr
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{ $$ = makeIf($2, $4, $6); }
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| expr_op
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;
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expr_op
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: '!' expr_op %prec NEG { $$ = makeOpNot($2); }
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| expr_op EQ expr_op { $$ = makeOpEq($1, $3); }
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| expr_op NEQ expr_op { $$ = makeOpNEq($1, $3); }
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| expr_op AND expr_op { $$ = makeOpAnd($1, $3); }
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| expr_op OR expr_op { $$ = makeOpOr($1, $3); }
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| expr_op IMPL expr_op { $$ = makeOpImpl($1, $3); }
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| expr_op UPDATE expr_op { $$ = makeOpUpdate($1, $3); }
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| expr_op '~' expr_op { $$ = makeSubPath($1, $3); }
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| expr_op '?' ID { $$ = makeOpHasAttr($1, $3); }
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| expr_op '+' expr_op { $$ = makeOpPlus($1, $3); }
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| expr_op CONCAT expr_op { $$ = makeOpConcat($1, $3); }
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| expr_app
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;
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expr_app
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: expr_app expr_select
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{ $$ = makeCall($1, $2); }
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| expr_select { $$ = $1; }
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;
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expr_select
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: expr_select '.' ID
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{ $$ = makeSelect($1, $3); }
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| expr_simple { $$ = $1; }
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;
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expr_simple
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: ID { $$ = makeVar($1); }
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| INT { $$ = makeInt(ATgetInt((ATermInt) $1)); }
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| '"' string_parts '"' {
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/* For efficiency, and to simplify parse trees a bit. */
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if ($2 == ATempty) $$ = makeStr(toATerm(""), ATempty);
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else if (ATgetNext($2) == ATempty) $$ = ATgetFirst($2);
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else $$ = makeConcatStrings(ATreverse($2));
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}
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| IND_STRING_OPEN ind_string_parts IND_STRING_CLOSE {
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$$ = stripIndentation(ATreverse($2));
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}
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| PATH { $$ = makePath(toATerm(absPath(aterm2String($1), data->basePath))); }
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| URI { $$ = makeStr($1, ATempty); }
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| '(' expr ')' { $$ = $2; }
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/* Let expressions `let {..., body = ...}' are just desugared
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into `(rec {..., body = ...}).body'. */
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| LET '{' binds '}'
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{ $$ = makeSelect(fixAttrs(true, $3), toATerm("body")); }
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| REC '{' binds '}'
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{ $$ = fixAttrs(true, $3); }
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| '{' binds '}'
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{ $$ = fixAttrs(false, $2); }
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| '[' expr_list ']' { $$ = makeList(ATreverse($2)); }
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;
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string_parts
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: string_parts STR { $$ = ATinsert($1, $2); }
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| string_parts DOLLAR_CURLY expr '}' { backToString(scanner); $$ = ATinsert($1, $3); }
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| { $$ = ATempty; }
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;
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ind_string_parts
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: ind_string_parts IND_STR { $$ = ATinsert($1, $2); }
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| ind_string_parts DOLLAR_CURLY expr '}' { backToIndString(scanner); $$ = ATinsert($1, $3); }
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| { $$ = ATempty; }
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;
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pattern
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: pattern2 '@' pattern { $$ = makeAtPat($1, $3); }
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| pattern2
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;
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pattern2
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: ID { $$ = makeVarPat($1); }
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| '{' formals '}' { $$ = makeAttrsPat($2.formals, $2.ellipsis ? eTrue : eFalse); }
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;
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binds
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: binds bind { $$ = ATinsert($1, $2); }
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| { $$ = ATempty; }
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;
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bind
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: attrpath '=' expr ';'
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{ $$ = makeBindAttrPath(ATreverse($1), $3, CUR_POS); }
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| INHERIT inheritsrc ids ';'
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{ $$ = makeInherit($2, $3, CUR_POS); }
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;
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inheritsrc
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|
: '(' expr ')' { $$ = $2; }
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| { $$ = makeScope(); }
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;
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ids: ids ID { $$ = ATinsert($1, $2); } | { $$ = ATempty; };
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attrpath
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: attrpath '.' ID { $$ = ATinsert($1, $3); }
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| ID { $$ = ATmakeList1($1); }
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;
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|
expr_list
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: expr_list expr_select { $$ = ATinsert($1, $2); }
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| { $$ = ATempty; }
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;
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formals
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: formal ',' formals /* !!! right recursive */
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{ $$.formals = ATinsert($3.formals, $1); $$.ellipsis = $3.ellipsis; }
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| formal
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{ $$.formals = ATinsert(ATempty, $1); $$.ellipsis = false; }
|
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|
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{ $$.formals = ATempty; $$.ellipsis = false; }
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| ELLIPSIS
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{ $$.formals = ATempty; $$.ellipsis = true; }
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;
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|
|
formal
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: ID { $$ = makeFormal($1, makeNoDefaultValue()); }
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| ID '?' expr { $$ = makeFormal($1, makeDefaultValue($3)); }
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;
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|
%%
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#include "eval.hh"
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#include <sys/types.h>
|
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#include <sys/stat.h>
|
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#include <fcntl.h>
|
|
#include <unistd.h>
|
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|
|
|
|
namespace nix {
|
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|
|
|
|
static Expr parse(EvalState & state,
|
|
const char * text, const Path & path,
|
|
const Path & basePath)
|
|
{
|
|
yyscan_t scanner;
|
|
ParseData data;
|
|
data.basePath = basePath;
|
|
data.path = path;
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|
|
yylex_init(&scanner);
|
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yy_scan_string(text, scanner);
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int res = yyparse(scanner, &data);
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yylex_destroy(scanner);
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|
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if (res) throw ParseError(data.error);
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|
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try {
|
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checkVarDefs(state.primOps, data.result);
|
|
} catch (Error & e) {
|
|
throw ParseError(format("%1%, in `%2%'") % e.msg() % path);
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|
}
|
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return data.result;
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}
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|
|
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Expr parseExprFromFile(EvalState & state, Path path)
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{
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assert(path[0] == '/');
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|
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#if 0
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/* Perhaps this is already an imploded parse tree? */
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Expr e = ATreadFromNamedFile(path.c_str());
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if (e) return e;
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#endif
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/* If `path' is a symlink, follow it. This is so that relative
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|
path references work. */
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struct stat st;
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while (true) {
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if (lstat(path.c_str(), &st))
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throw SysError(format("getting status of `%1%'") % path);
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if (!S_ISLNK(st.st_mode)) break;
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|
path = absPath(readLink(path), dirOf(path));
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|
}
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/* If `path' refers to a directory, append `/default.nix'. */
|
|
if (stat(path.c_str(), &st))
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|
throw SysError(format("getting status of `%1%'") % path);
|
|
if (S_ISDIR(st.st_mode))
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path = canonPath(path + "/default.nix");
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|
|
|
/* Read and parse the input file. */
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|
return parse(state, readFile(path).c_str(), path, dirOf(path));
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|
}
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Expr parseExprFromString(EvalState & state,
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|
const string & s, const Path & basePath)
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|
{
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|
return parse(state, s.c_str(), "(string)", basePath);
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|
}
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|
|
|
|
|
}
|