forked from lix-project/lix
541 lines
14 KiB
Plaintext
541 lines
14 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 Expr fixAttrs(int recursive, ATermList as)
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{
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ATermList bs = ATempty, cs = ATempty;
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ATermList * is = recursive ? &cs : &bs;
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for (ATermIterator i(as); i; ++i) {
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ATermList names;
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Expr src;
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ATerm 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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Expr rhs = fromScope ? makeVar(*j) : makeSelect(src, *j);
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*is = ATinsert(*is, makeBind(*j, rhs, pos));
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}
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} else bs = ATinsert(bs, *i);
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}
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if (recursive)
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return makeRec(bs, cs);
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else
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return makeAttrs(bs);
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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 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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{ $$ = makeFunction($1, $3, CUR_POS); }
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| ASSERT expr ';' expr_function
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{ $$ = 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(1, ATinsert($2, makeBind(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(1, $3), toATerm("body")); }
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| REC '{' binds '}'
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{ $$ = fixAttrs(1, $3); }
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| '{' binds '}'
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{ $$ = fixAttrs(0, $2); }
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| '[' expr_list ']' { $$ = makeList($2); }
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;
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string_parts
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: string_parts STR { $$ = 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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: ID '=' expr ';'
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{ $$ = makeBind($1, $3, CUR_POS); }
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| INHERIT inheritsrc ids ';'
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{ $$ = 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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expr_list
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: expr_select expr_list { $$ = ATinsert($2, $1); }
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/* yes, this is right-recursive, but it doesn't matter since
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otherwise we would need ATreverse which requires unbounded
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stack space */
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| { $$ = ATempty; }
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;
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formals
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: formal ',' formals /* idem - 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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{ $$.formals = ATempty; $$.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>
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#include <unistd.h>
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namespace nix {
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static void checkAttrs(ATermMap & names, ATermList bnds)
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{
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for (ATermIterator i(bnds); i; ++i) {
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ATerm name;
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Expr e;
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ATerm pos;
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if (!matchBind(*i, name, e, pos)) abort(); /* can't happen */
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if (names.get(name))
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throw EvalError(format("duplicate attribute `%1%' at %2%")
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% aterm2String(name) % showPos(pos));
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names.set(name, name);
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}
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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 EvalError(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 EvalError(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 checkAttrSets(ATerm e)
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{
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ATerm pat, body, pos;
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if (matchFunction(e, pat, body, pos)) {
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ATermMap map(16);
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checkPatternVars(pos, map, pat);
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}
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ATermList bnds;
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if (matchAttrs(e, bnds)) {
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ATermMap names(ATgetLength(bnds));
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checkAttrs(names, bnds);
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}
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ATermList rbnds, nrbnds;
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if (matchRec(e, rbnds, nrbnds)) {
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ATermMap names(ATgetLength(rbnds) + ATgetLength(nrbnds));
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checkAttrs(names, rbnds);
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checkAttrs(names, nrbnds);
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}
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if (ATgetType(e) == AT_APPL) {
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int arity = ATgetArity(ATgetAFun(e));
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for (int i = 0; i < arity; ++i)
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checkAttrSets(ATgetArgument(e, i));
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}
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else if (ATgetType(e) == AT_LIST)
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for (ATermIterator i((ATermList) e); i; ++i)
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checkAttrSets(*i);
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}
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static Expr parse(EvalState & state,
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const char * text, const Path & path,
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const Path & basePath)
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{
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yyscan_t scanner;
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ParseData data;
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data.basePath = basePath;
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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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if (res) throw EvalError(data.error);
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try {
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checkVarDefs(state.primOps, data.result);
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} catch (Error & e) {
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throw EvalError(format("%1%, in `%2%'") % e.msg() % path);
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}
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checkAttrSets(data.result);
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return data.result;
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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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#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'. */
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if (stat(path.c_str(), &st))
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throw SysError(format("getting status of `%1%'") % path);
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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,
|
|
const string & s, const Path & basePath)
|
|
{
|
|
return parse(state, s.c_str(), "(string)", basePath);
|
|
}
|
|
|
|
|
|
}
|