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Diffstat (limited to 'src/libexpr/parser.y')
| -rw-r--r-- | src/libexpr/parser.y | 650 |
1 files changed, 650 insertions, 0 deletions
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y new file mode 100644 index 000000000000..8a084fea0697 --- /dev/null +++ b/src/libexpr/parser.y @@ -0,0 +1,650 @@ +%glr-parser +%pure-parser +%locations +%error-verbose +%defines +/* %no-lines */ +%parse-param { void * scanner } +%parse-param { nix::ParseData * data } +%lex-param { void * scanner } +%lex-param { nix::ParseData * data } +%expect 1 +%expect-rr 1 + +%code requires { + +#ifndef BISON_HEADER +#define BISON_HEADER + +#include "util.hh" + +#include "nixexpr.hh" +#include "eval.hh" + +namespace nix { + + struct ParseData + { + EvalState & state; + SymbolTable & symbols; + Expr * result; + Path basePath; + Symbol path; + string error; + Symbol sLetBody; + ParseData(EvalState & state) + : state(state) + , symbols(state.symbols) + , sLetBody(symbols.create("<let-body>")) + { }; + }; + +} + +#define YY_DECL int yylex \ + (YYSTYPE * yylval_param, YYLTYPE * yylloc_param, yyscan_t yyscanner, nix::ParseData * data) + +#endif + +} + +%{ + +#include "parser-tab.hh" +#include "lexer-tab.hh" + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +YY_DECL; + +using namespace nix; + + +namespace nix { + + +static void dupAttr(const AttrPath & attrPath, const Pos & pos, const Pos & prevPos) +{ + throw ParseError(format("attribute `%1%' at %2% already defined at %3%") + % showAttrPath(attrPath) % pos % prevPos); +} + + +static void dupAttr(Symbol attr, const Pos & pos, const Pos & prevPos) +{ + throw ParseError(format("attribute `%1%' at %2% already defined at %3%") + % attr % pos % prevPos); +} + + +static void addAttr(ExprAttrs * attrs, AttrPath & attrPath, + Expr * e, const Pos & pos) +{ + AttrPath::iterator i; + // All attrpaths have at least one attr + assert(!attrPath.empty()); + for (i = attrPath.begin(); i + 1 < attrPath.end(); i++) { + if (i->symbol.set()) { + ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol); + if (j != attrs->attrs.end()) { + if (!j->second.inherited) { + ExprAttrs * attrs2 = dynamic_cast<ExprAttrs *>(j->second.e); + if (!attrs2) dupAttr(attrPath, pos, j->second.pos); + attrs = attrs2; + } else + dupAttr(attrPath, pos, j->second.pos); + } else { + ExprAttrs * nested = new ExprAttrs; + attrs->attrs[i->symbol] = ExprAttrs::AttrDef(nested, pos); + attrs = nested; + } + } else { + ExprAttrs *nested = new ExprAttrs; + attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, nested, pos)); + attrs = nested; + } + } + if (i->symbol.set()) { + ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol); + if (j != attrs->attrs.end()) { + dupAttr(attrPath, pos, j->second.pos); + } else { + attrs->attrs[i->symbol] = ExprAttrs::AttrDef(e, pos); + e->setName(i->symbol); + } + } else { + attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, e, pos)); + } +} + + +static void addFormal(const Pos & pos, Formals * formals, const Formal & formal) +{ + if (formals->argNames.find(formal.name) != formals->argNames.end()) + throw ParseError(format("duplicate formal function argument `%1%' at %2%") + % formal.name % pos); + formals->formals.push_front(formal); + formals->argNames.insert(formal.name); +} + + +static Expr * stripIndentation(SymbolTable & symbols, vector<Expr *> & es) +{ + if (es.empty()) return new ExprString(symbols.create("")); + + /* Figure out the minimum indentation. Note that by design + whitespace-only final lines are not taken into account. (So + the " " in "\n ''" is ignored, but the " " in "\n foo''" is.) */ + bool atStartOfLine = true; /* = seen only whitespace in the current line */ + unsigned int minIndent = 1000000; + unsigned int curIndent = 0; + foreach (vector<Expr *>::iterator, i, es) { + ExprIndStr * e = dynamic_cast<ExprIndStr *>(*i); + if (!e) { + /* Anti-quotations end the current start-of-line whitespace. */ + if (atStartOfLine) { + atStartOfLine = false; + if (curIndent < minIndent) minIndent = curIndent; + } + continue; + } + for (unsigned int j = 0; j < e->s.size(); ++j) { + if (atStartOfLine) { + if (e->s[j] == ' ') + curIndent++; + else if (e->s[j] == '\n') { + /* Empty line, doesn't influence minimum + indentation. */ + curIndent = 0; + } else { + atStartOfLine = false; + if (curIndent < minIndent) minIndent = curIndent; + } + } else if (e->s[j] == '\n') { + atStartOfLine = true; + curIndent = 0; + } + } + } + + /* Strip spaces from each line. */ + vector<Expr *> * es2 = new vector<Expr *>; + atStartOfLine = true; + unsigned int curDropped = 0; + unsigned int n = es.size(); + for (vector<Expr *>::iterator i = es.begin(); i != es.end(); ++i, --n) { + ExprIndStr * e = dynamic_cast<ExprIndStr *>(*i); + if (!e) { + atStartOfLine = false; + curDropped = 0; + es2->push_back(*i); + continue; + } + + string s2; + for (unsigned int j = 0; j < e->s.size(); ++j) { + if (atStartOfLine) { + if (e->s[j] == ' ') { + if (curDropped++ >= minIndent) + s2 += e->s[j]; + } + else if (e->s[j] == '\n') { + curDropped = 0; + s2 += e->s[j]; + } else { + atStartOfLine = false; + curDropped = 0; + s2 += e->s[j]; + } + } else { + s2 += e->s[j]; + if (e->s[j] == '\n') atStartOfLine = true; + } + } + + /* Remove the last line if it is empty and consists only of + spaces. */ + if (n == 1) { + string::size_type p = s2.find_last_of('\n'); + if (p != string::npos && s2.find_first_not_of(' ', p + 1) == string::npos) + s2 = string(s2, 0, p + 1); + } + + es2->push_back(new ExprString(symbols.create(s2))); + } + + /* If this is a single string, then don't do a concatenation. */ + return es2->size() == 1 && dynamic_cast<ExprString *>((*es2)[0]) ? (*es2)[0] : new ExprConcatStrings(true, es2); +} + + +void backToString(yyscan_t scanner); +void backToIndString(yyscan_t scanner); + + +static Pos makeCurPos(const YYLTYPE & loc, ParseData * data) +{ + return Pos(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%") + % error % makeCurPos(*loc, data)).str(); +} + + +%} + +%union { + // !!! We're probably leaking stuff here. + nix::Expr * e; + nix::ExprList * list; + nix::ExprAttrs * attrs; + nix::Formals * formals; + nix::Formal * formal; + nix::NixInt n; + const char * id; // !!! -> Symbol + char * path; + char * uri; + std::vector<nix::AttrName> * attrNames; + std::vector<nix::Expr *> * string_parts; +} + +%type <e> start expr expr_function expr_if expr_op +%type <e> expr_app expr_select expr_simple +%type <list> expr_list +%type <attrs> binds +%type <formals> formals +%type <formal> formal +%type <attrNames> attrs attrpath +%type <string_parts> string_parts_interpolated ind_string_parts +%type <e> string_parts string_attr +%type <id> attr +%token <id> ID ATTRPATH +%token <e> STR IND_STR +%token <n> INT +%token <path> PATH SPATH +%token <uri> URI +%token IF THEN ELSE ASSERT WITH LET IN REC INHERIT EQ NEQ AND OR IMPL OR_KW +%token DOLLAR_CURLY /* == ${ */ +%token IND_STRING_OPEN IND_STRING_CLOSE +%token ELLIPSIS + +%nonassoc IMPL +%left OR +%left AND +%nonassoc EQ NEQ +%left '<' '>' LEQ GEQ +%right UPDATE +%left NOT +%left '+' '-' +%left '*' '/' +%right CONCAT +%nonassoc '?' +%nonassoc '~' +%nonassoc NEGATE + +%% + +start: expr { data->result = $1; }; + +expr: expr_function; + +expr_function + : ID ':' expr_function + { $$ = new ExprLambda(CUR_POS, data->symbols.create($1), false, 0, $3); } + | '{' formals '}' ':' expr_function + { $$ = new ExprLambda(CUR_POS, data->symbols.create(""), true, $2, $5); } + | '{' formals '}' '@' ID ':' expr_function + { $$ = new ExprLambda(CUR_POS, data->symbols.create($5), true, $2, $7); } + | ID '@' '{' formals '}' ':' expr_function + { $$ = new ExprLambda(CUR_POS, data->symbols.create($1), true, $4, $7); } + | ASSERT expr ';' expr_function + { $$ = new ExprAssert(CUR_POS, $2, $4); } + | WITH expr ';' expr_function + { $$ = new ExprWith(CUR_POS, $2, $4); } + | LET binds IN expr_function + { if (!$2->dynamicAttrs.empty()) + throw ParseError(format("dynamic attributes not allowed in let at %1%") + % CUR_POS); + $$ = new ExprLet($2, $4); + } + | expr_if + ; + +expr_if + : IF expr THEN expr ELSE expr { $$ = new ExprIf($2, $4, $6); } + | expr_op + ; + +expr_op + : '!' expr_op %prec NOT { $$ = new ExprOpNot($2); } +| '-' expr_op %prec NEGATE { $$ = new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("sub")), new ExprInt(0)), $2); } + | expr_op EQ expr_op { $$ = new ExprOpEq($1, $3); } + | expr_op NEQ expr_op { $$ = new ExprOpNEq($1, $3); } + | expr_op '<' expr_op { $$ = new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("lessThan")), $1), $3); } + | expr_op LEQ expr_op { $$ = new ExprOpNot(new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("lessThan")), $3), $1)); } + | expr_op '>' expr_op { $$ = new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("lessThan")), $3), $1); } + | expr_op GEQ expr_op { $$ = new ExprOpNot(new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("lessThan")), $1), $3)); } + | expr_op AND expr_op { $$ = new ExprOpAnd($1, $3); } + | expr_op OR expr_op { $$ = new ExprOpOr($1, $3); } + | expr_op IMPL expr_op { $$ = new ExprOpImpl($1, $3); } + | expr_op UPDATE expr_op { $$ = new ExprOpUpdate($1, $3); } + | expr_op '?' attrpath { $$ = new ExprOpHasAttr($1, *$3); } + | expr_op '+' expr_op + { vector<Expr *> * l = new vector<Expr *>; + l->push_back($1); + l->push_back($3); + $$ = new ExprConcatStrings(false, l); + } + | expr_op '-' expr_op { $$ = new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("sub")), $1), $3); } + | expr_op '*' expr_op { $$ = new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("mul")), $1), $3); } + | expr_op '/' expr_op { $$ = new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("div")), $1), $3); } + | expr_op CONCAT expr_op { $$ = new ExprOpConcatLists($1, $3); } + | expr_app + ; + +expr_app + : expr_app expr_select + { $$ = new ExprApp($1, $2); } + | expr_select { $$ = $1; } + ; + +expr_select + : expr_simple '.' attrpath + { $$ = new ExprSelect($1, *$3, 0); } + | expr_simple '.' attrpath OR_KW expr_select + { $$ = new ExprSelect($1, *$3, $5); } + | /* Backwards compatibility: because Nixpkgs has a rarely used + function named ‘or’, allow stuff like ‘map or [...]’. */ + expr_simple OR_KW + { $$ = new ExprApp($1, new ExprVar(CUR_POS, data->symbols.create("or"))); } + | expr_simple { $$ = $1; } + ; + +expr_simple + : ID { + if (strcmp($1, "__curPos") == 0) + $$ = new ExprPos(CUR_POS); + else + $$ = new ExprVar(CUR_POS, data->symbols.create($1)); + } + | INT { $$ = new ExprInt($1); } + | '"' string_parts '"' { $$ = $2; } + | IND_STRING_OPEN ind_string_parts IND_STRING_CLOSE { + $$ = stripIndentation(data->symbols, *$2); + } + | PATH { $$ = new ExprPath(absPath($1, data->basePath)); } + | SPATH { + string path($1 + 1, strlen($1) - 2); + Path path2 = data->state.findFile(path); + /* The file wasn't found in the search path. However, we can't + throw an error here, because the expression might never be + evaluated. So return an expression that lazily calls + ‘throw’. */ + $$ = path2 == "" + ? (Expr * ) new ExprApp( + new ExprBuiltin(data->symbols.create("throw")), + new ExprString(data->symbols.create( + (format("file `%1%' was not found in the Nix search path (add it using $NIX_PATH or -I)") % path).str()))) + : (Expr * ) new ExprPath(path2); + } + | URI { $$ = new ExprString(data->symbols.create($1)); } + | '(' expr ')' { $$ = $2; } + /* Let expressions `let {..., body = ...}' are just desugared + into `(rec {..., body = ...}).body'. */ + | LET '{' binds '}' + { $3->recursive = true; $$ = new ExprSelect($3, data->symbols.create("body")); } + | REC '{' binds '}' + { $3->recursive = true; $$ = $3; } + | '{' binds '}' + { $$ = $2; } + | '[' expr_list ']' { $$ = $2; } + ; + +string_parts + : STR + | string_parts_interpolated { $$ = new ExprConcatStrings(true, $1); } + | { $$ = new ExprString(data->symbols.create("")); } + ; + +string_parts_interpolated + : string_parts_interpolated STR { $$ = $1; $1->push_back($2); } + | string_parts_interpolated DOLLAR_CURLY expr '}' { backToString(scanner); $$ = $1; $1->push_back($3); } + | STR DOLLAR_CURLY expr '}' + { + backToString(scanner); + $$ = new vector<Expr *>; + $$->push_back($1); + $$->push_back($3); + } + | DOLLAR_CURLY expr '}' + { + backToString(scanner); + $$ = new vector<Expr *>; + $$->push_back($2); + } + ; + +ind_string_parts + : ind_string_parts IND_STR { $$ = $1; $1->push_back($2); } + | ind_string_parts DOLLAR_CURLY expr '}' { backToIndString(scanner); $$ = $1; $1->push_back($3); } + | { $$ = new vector<Expr *>; } + ; + +binds + : binds attrpath '=' expr ';' { $$ = $1; addAttr($$, *$2, $4, makeCurPos(@2, data)); } + | binds INHERIT attrs ';' + { $$ = $1; + foreach (AttrPath::iterator, i, *$3) { + if ($$->attrs.find(i->symbol) != $$->attrs.end()) + dupAttr(i->symbol, makeCurPos(@3, data), $$->attrs[i->symbol].pos); + Pos pos = makeCurPos(@3, data); + $$->attrs[i->symbol] = ExprAttrs::AttrDef(new ExprVar(CUR_POS, i->symbol), pos, true); + } + } + | binds INHERIT '(' expr ')' attrs ';' + { $$ = $1; + /* !!! Should ensure sharing of the expression in $4. */ + foreach (AttrPath::iterator, i, *$6) { + if ($$->attrs.find(i->symbol) != $$->attrs.end()) + dupAttr(i->symbol, makeCurPos(@6, data), $$->attrs[i->symbol].pos); + $$->attrs[i->symbol] = ExprAttrs::AttrDef(new ExprSelect($4, i->symbol), makeCurPos(@6, data)); + } + } + | { $$ = new ExprAttrs; } + ; + +attrs + : attrs attr { $$ = $1; $1->push_back(AttrName(data->symbols.create($2))); } + | attrs string_attr + { $$ = $1; + ExprString *str = dynamic_cast<ExprString *>($2); + if (str) { + $$->push_back(AttrName(str->s)); + delete str; + } else + throw ParseError(format("dynamic attributes not allowed in inherit at %1%") + % makeCurPos(@2, data)); + } + | { $$ = new AttrPath; } + ; + +attrpath + : attrpath '.' attr { $$ = $1; $1->push_back(AttrName(data->symbols.create($3))); } + | attrpath '.' string_attr + { $$ = $1; + ExprString *str = dynamic_cast<ExprString *>($3); + if (str) { + $$->push_back(AttrName(str->s)); + delete str; + } else + $$->push_back(AttrName($3)); + } + | attr { $$ = new vector<AttrName>; $$->push_back(AttrName(data->symbols.create($1))); } + | string_attr + { $$ = new vector<AttrName>; + ExprString *str = dynamic_cast<ExprString *>($1); + if (str) { + $$->push_back(AttrName(str->s)); + delete str; + } else + $$->push_back(AttrName($1)); + } + ; + +attr + : ID { $$ = $1; } + | OR_KW { $$ = "or"; } + ; + +string_attr + : '"' string_parts '"' { $$ = $2; } + | DOLLAR_CURLY expr '}' { $$ = new ExprConcatStrings(true, new vector<Expr*>(1, $2)); } + ; + +expr_list + : expr_list expr_select { $$ = $1; $1->elems.push_back($2); /* !!! dangerous */ } + | { $$ = new ExprList; } + ; + +formals + : formal ',' formals + { $$ = $3; addFormal(CUR_POS, $$, *$1); } + | formal + { $$ = new Formals; addFormal(CUR_POS, $$, *$1); $$->ellipsis = false; } + | + { $$ = new Formals; $$->ellipsis = false; } + | ELLIPSIS + { $$ = new Formals; $$->ellipsis = true; } + ; + +formal + : ID { $$ = new Formal(data->symbols.create($1), 0); } + | ID '?' expr { $$ = new Formal(data->symbols.create($1), $3); } + ; + +%% + + +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> + +#include <eval.hh> + + +namespace nix { + + +Expr * EvalState::parse(const char * text, + const Path & path, const Path & basePath, StaticEnv & staticEnv) +{ + yyscan_t scanner; + ParseData data(*this); + data.basePath = basePath; + data.path = data.symbols.create(path); + + yylex_init(&scanner); + yy_scan_string(text, scanner); + int res = yyparse(scanner, &data); + yylex_destroy(scanner); + + if (res) throw ParseError(data.error); + + data.result->bindVars(staticEnv); + + return data.result; +} + + +Path resolveExprPath(Path path) +{ + assert(path[0] == '/'); + + /* 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 (S_ISDIR(st.st_mode)) + path = canonPath(path + "/default.nix"); + + return path; +} + + +Expr * EvalState::parseExprFromFile(const Path & path) +{ + return parse(readFile(path).c_str(), path, dirOf(path), staticBaseEnv); +} + + +Expr * EvalState::parseExprFromString(const string & s, const Path & basePath, StaticEnv & staticEnv) +{ + return parse(s.c_str(), "(string)", basePath, staticEnv); +} + + +Expr * EvalState::parseExprFromString(const string & s, const Path & basePath) +{ + return parseExprFromString(s, basePath, staticBaseEnv); +} + + +void EvalState::addToSearchPath(const string & s) +{ + size_t pos = s.find('='); + string prefix; + Path path; + if (pos == string::npos) { + path = s; + } else { + prefix = string(s, 0, pos); + path = string(s, pos + 1); + } + + path = absPath(path); + if (pathExists(path)) { + debug(format("adding path `%1%' to the search path") % path); + searchPath.insert(searchPathInsertionPoint, std::pair<string, Path>(prefix, path)); + } +} + + +Path EvalState::findFile(const string & path) +{ + foreach (SearchPath::iterator, i, searchPath) { + Path res; + if (i->first.empty()) + res = i->second + "/" + path; + else { + if (path.compare(0, i->first.size(), i->first) != 0 || + (path.size() > i->first.size() && path[i->first.size()] != '/')) + continue; + res = i->second + + (path.size() == i->first.size() ? "" : "/" + string(path, i->first.size())); + } + if (pathExists(res)) return canonPath(res); + } + return ""; +} + + +} |