%glr-parser %pure-parser %locations %error-verbose %defines /* %no-lines */ %parse-param { yyscan_t scanner } %parse-param { ParseData * data } %lex-param { yyscan_t scanner } %{ /* Newer versions of Bison copy the declarations below to parser-tab.hh, which sucks bigtime since lexer.l doesn't want that stuff. So allow it to be excluded. */ #ifndef BISON_HEADER_HACK #define BISON_HEADER_HACK #include <stdio.h> #include <stdlib.h> #include <string.h> #include "aterm.hh" #include "util.hh" #include "parser-tab.hh" #include "lexer-tab.hh" #include "nixexpr.hh" #include "nixexpr-ast.hh" using namespace nix; namespace nix { struct ParseData { Expr result; Path basePath; Path path; string error; }; static Expr fixAttrs(int recursive, ATermList as) { ATermList bs = ATempty, cs = ATempty; ATermList * is = recursive ? &cs : &bs; for (ATermIterator i(as); i; ++i) { ATermList names; Expr src; ATerm pos; if (matchInherit(*i, src, names, pos)) { bool fromScope = matchScope(src); for (ATermIterator j(names); j; ++j) { Expr rhs = fromScope ? makeVar(*j) : makeSelect(src, *j); *is = ATinsert(*is, makeBind(*j, rhs, pos)); } } else bs = ATinsert(bs, *i); } if (recursive) return makeRec(bs, cs); else return makeAttrs(bs); } void backToString(yyscan_t scanner); static Pos makeCurPos(YYLTYPE * loc, ParseData * data) { return makePos(toATerm(data->path), loc->first_line, loc->first_column); } #define CUR_POS makeCurPos(yylocp, data) } void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * error) { data->error = (format("%1%, at `%2%':%3%:%4%") % error % data->path % loc->first_line % loc->first_column).str(); } /* Make sure that the parse stack is scanned by the ATerm garbage collector. */ static void * mallocAndProtect(size_t size) { void * p = malloc(size); if (p) ATprotectMemory(p, size); return p; } static void freeAndUnprotect(void * p) { ATunprotectMemory(p); free(p); } #define YYMALLOC mallocAndProtect #define YYFREE freeAndUnprotect #endif %} %union { ATerm t; ATermList ts; } %type <t> start expr expr_function expr_if expr_op %type <t> expr_app expr_select expr_simple bind inheritsrc formal %type <ts> binds ids expr_list formals string_parts %token <t> ID INT STR PATH URI %token IF THEN ELSE ASSERT WITH LET IN REC INHERIT EQ NEQ AND OR IMPL %token DOLLAR_CURLY /* == ${ */ %nonassoc IMPL %left OR %left AND %nonassoc EQ NEQ %right UPDATE %left NEG %left '+' %right CONCAT %nonassoc '?' %nonassoc '~' %% start: expr { data->result = $1; }; expr: expr_function; expr_function : '{' formals '}' ':' expr_function { $$ = makeFunction($2, $5, CUR_POS); } | ID ':' expr_function { $$ = makeFunction1($1, $3, CUR_POS); } | ASSERT expr ';' expr_function { $$ = makeAssert($2, $4, CUR_POS); } | WITH expr ';' expr_function { $$ = makeWith($2, $4, CUR_POS); } | LET binds IN expr_function { $$ = makeSelect(fixAttrs(1, ATinsert($2, makeBind(toATerm("<let-body>"), $4, CUR_POS))), toATerm("<let-body>")); } | expr_if ; expr_if : IF expr THEN expr ELSE expr { $$ = makeIf($2, $4, $6); } | expr_op ; expr_op : '!' expr_op %prec NEG { $$ = makeOpNot($2); } | expr_op EQ expr_op { $$ = makeOpEq($1, $3); } | expr_op NEQ expr_op { $$ = makeOpNEq($1, $3); } | expr_op AND expr_op { $$ = makeOpAnd($1, $3); } | expr_op OR expr_op { $$ = makeOpOr($1, $3); } | expr_op IMPL expr_op { $$ = makeOpImpl($1, $3); } | expr_op UPDATE expr_op { $$ = makeOpUpdate($1, $3); } | expr_op '~' expr_op { $$ = makeSubPath($1, $3); } | expr_op '?' ID { $$ = makeOpHasAttr($1, $3); } | expr_op '+' expr_op { $$ = makeOpPlus($1, $3); } | expr_op CONCAT expr_op { $$ = makeOpConcat($1, $3); } | expr_app ; expr_app : expr_app expr_select { $$ = makeCall($1, $2); } | expr_select { $$ = $1; } ; expr_select : expr_select '.' ID { $$ = makeSelect($1, $3); } | expr_simple { $$ = $1; } ; expr_simple : ID { $$ = makeVar($1); } | INT { $$ = makeInt(ATgetInt((ATermInt) $1)); } | '"' string_parts '"' { /* For efficiency, and to simplify parse trees a bit. */ if ($2 == ATempty) $$ = makeStr(toATerm(""), ATempty); else if (ATgetNext($2) == ATempty) $$ = ATgetFirst($2); else $$ = makeConcatStrings(ATreverse($2)); } | PATH { $$ = makePath(toATerm(absPath(aterm2String($1), data->basePath))); } | URI { $$ = makeStr($1, ATempty); } | '(' expr ')' { $$ = $2; } /* Let expressions `let {..., body = ...}' are just desugared into `(rec {..., body = ...}).body'. */ | LET '{' binds '}' { $$ = makeSelect(fixAttrs(1, $3), toATerm("body")); } | REC '{' binds '}' { $$ = fixAttrs(1, $3); } | '{' binds '}' { $$ = fixAttrs(0, $2); } | '[' expr_list ']' { $$ = makeList($2); } ; string_parts : string_parts STR { $$ = ATinsert($1, $2); } | string_parts DOLLAR_CURLY expr '}' { backToString(scanner); $$ = ATinsert($1, $3); } | { $$ = ATempty; } ; binds : binds bind { $$ = ATinsert($1, $2); } | { $$ = ATempty; } ; bind : ID '=' expr ';' { $$ = makeBind($1, $3, CUR_POS); } | INHERIT inheritsrc ids ';' { $$ = makeInherit($2, $3, CUR_POS); } ; inheritsrc : '(' expr ')' { $$ = $2; } | { $$ = makeScope(); } ; ids: ids ID { $$ = ATinsert($1, $2); } | { $$ = ATempty; }; expr_list : expr_select expr_list { $$ = ATinsert($2, $1); } /* yes, this is right-recursive, but it doesn't matter since otherwise we would need ATreverse which requires unbounded stack space */ | { $$ = ATempty; } ; formals : formal ',' formals { $$ = ATinsert($3, $1); } /* idem - right recursive */ | formal { $$ = ATinsert(ATempty, $1); } | { $$ = ATempty; } ; formal : ID { $$ = makeFormal($1, makeUnrestrictedValues(), makeNoDefaultValue()); } | ID ':' '[' expr_list ']' { $$ = makeFormal($1, makeValidValues($4), makeNoDefaultValue()); } | ID '?' expr { $$ = makeFormal($1, makeUnrestrictedValues(), makeDefaultValue($3)); } ; %% #include "eval.hh" #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> namespace nix { static void checkAttrs(ATermMap & names, ATermList bnds) { for (ATermIterator i(bnds); i; ++i) { ATerm name; Expr e; ATerm pos; if (!matchBind(*i, name, e, pos)) abort(); /* can't happen */ if (names.get(name)) throw EvalError(format("duplicate attribute `%1%' at %2%") % aterm2String(name) % showPos(pos)); names.set(name, name); } } static void checkAttrSets(ATerm e) { ATermList formals; ATerm body, pos; if (matchFunction(e, formals, body, pos)) { ATermMap names(ATgetLength(formals)); for (ATermIterator i(formals); i; ++i) { ATerm name; ATerm d1, d2; if (!matchFormal(*i, name, d1, d2)) abort(); if (names.get(name)) throw EvalError(format("duplicate formal function argument `%1%' at %2%") % aterm2String(name) % showPos(pos)); names.set(name, name); } } ATermList bnds; if (matchAttrs(e, bnds)) { ATermMap names(ATgetLength(bnds)); checkAttrs(names, bnds); } ATermList rbnds, nrbnds; if (matchRec(e, rbnds, nrbnds)) { ATermMap names(ATgetLength(rbnds) + ATgetLength(nrbnds)); checkAttrs(names, rbnds); checkAttrs(names, nrbnds); } if (ATgetType(e) == AT_APPL) { int arity = ATgetArity(ATgetAFun(e)); for (int i = 0; i < arity; ++i) checkAttrSets(ATgetArgument(e, i)); } else if (ATgetType(e) == AT_LIST) for (ATermIterator i((ATermList) e); i; ++i) checkAttrSets(*i); } 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; yylex_init(&scanner); yy_scan_string(text, scanner); int res = yyparse(scanner, &data); yylex_destroy(scanner); if (res) throw EvalError(data.error); try { checkVarDefs(state.primOps, data.result); } catch (Error & e) { throw EvalError(format("%1%, in `%2%'") % e.msg() % path); } checkAttrSets(data.result); return data.result; } Expr parseExprFromFile(EvalState & state, Path path) { assert(path[0] == '/'); #if 0 /* Perhaps this is already an imploded parse tree? */ Expr e = ATreadFromNamedFile(path.c_str()); if (e) return e; #endif /* If `path' is a symlink, follow it. This is so that relative path references work. */ struct stat st; while (true) { if (lstat(path.c_str(), &st)) throw SysError(format("getting status of `%1%'") % path); if (!S_ISLNK(st.st_mode)) break; path = absPath(readLink(path), dirOf(path)); } /* If `path' refers to a directory, append `/default.nix'. */ if (stat(path.c_str(), &st)) throw SysError(format("getting status of `%1%'") % 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)); } Expr parseExprFromString(EvalState & state, const string & s, const Path & basePath) { return parse(state, s.c_str(), "(string)", basePath); } }