feat(frontends/lean): add 'prelude' command, and init directory

library/init/default.lean

@@ -0,0 +1,7 @@
+/-
+Copyright (c) 2014 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Authors: Leonardo de Moura
+-/
+prelude

src/emacs/lean-syntax.el

@@ -8,7 +8,7 @@
 (require 'rx)
 
 (defconst lean-keywords
-  '("import" "reducible" "irreducible" "tactic_hint" "protected" "private" "opaque" "definition" "renaming"
+  '("import" "prelude" "reducible" "irreducible" "tactic_hint" "protected" "private" "opaque" "definition" "renaming"
     "hiding" "exposing" "parameter" "parameters" "begin" "proof" "qed" "conjecture" "constant" "constants"
     "hypothesis" "lemma" "corollary" "variable" "variables" "print" "theorem" "example"
     "context" "open" "as" "export" "axiom" "inductive" "with" "structure" "record" "universe" "universes"

src/frontends/lean/dependencies.cpp

@@ -12,8 +12,11 @@ Author: Leonardo de Moura
 #include "frontends/lean/scanner.h"
 
 namespace lean {
+
+
 bool display_deps(environment const & env, std::ostream & out, std::ostream & err, char const * fname) {
     name import("import");
+    name prelude("prelude");
     name period(".");
     std::ifstream in(fname);
     if (in.bad() || in.fail()) {
@@ -26,6 +29,25 @@ bool display_deps(environment const & env, std::ostream & out, std::ostream & er
     bool import_prefix = false;
     bool import_args   = false;
     bool ok            = true;
+    bool is_prelude    = false;
+    auto display_dep = [&](optional<unsigned> const & k, name const & f) {
+        import_args = true;
+        try {
+            std::string m_name = find_file(base, k, name_to_file(f), {".lean", ".olean", ".lua"});
+            int last_idx = m_name.find_last_of(".");
+            std::string rawname = m_name.substr(0, last_idx);
+            std::string ext = m_name.substr(last_idx);
+            if (ext == ".lean")
+                m_name = rawname + ".olean";
+            display_path(out, m_name);
+            import_prefix = true;
+            out << "\n";
+        } catch (exception & new_ex) {
+            err << "error: file '" << name_to_file(s.get_name_val()) << "' not found in the LEAN_PATH" << std::endl;
+            ok  = false;
+        }
+    };
+
     while (true) {
         scanner::token_kind t = scanner::token_kind::Identifier;
         try {
@@ -34,7 +56,11 @@ bool display_deps(environment const & env, std::ostream & out, std::ostream & er
             continue;
         }
         if (t == scanner::token_kind::Eof) {
+            if (!is_prelude)
+                display_dep(optional<unsigned>(), name("init"));
             return ok;
+        } else if (t == scanner::token_kind::CommandKeyword && s.get_token_info().value() == prelude) {
+            is_prelude = true;
         } else if (t == scanner::token_kind::CommandKeyword && s.get_token_info().value() == import) {
             k = optional<unsigned>();
             import_prefix = true;
@@ -44,22 +70,8 @@ bool display_deps(environment const & env, std::ostream & out, std::ostream & er
             else
                 k = *k + 1;
         } else if ((import_prefix || import_args) && t == scanner::token_kind::Identifier) {
-            import_args = true;
+            display_dep(k, s.get_name_val());
-            try {
+            k = optional<unsigned>();
-                std::string m_name = find_file(base, k, name_to_file(s.get_name_val()), {".lean", ".olean", ".lua"});
-                int last_idx = m_name.find_last_of(".");
-                std::string rawname = m_name.substr(0, last_idx);
-                std::string ext = m_name.substr(last_idx);
-                if (ext == ".lean")
-                    m_name = rawname + ".olean";
-                display_path(out, m_name);
-                k = optional<unsigned>();
-                import_prefix = true;
-                out << "\n";
-            } catch (exception & new_ex) {
-                err << "error: file '" << name_to_file(s.get_name_val()) << "' not found in the LEAN_PATH" << std::endl;
-                ok  = false;
-            }
         } else {
             import_args   = false;
             import_prefix = false;

src/frontends/lean/parser.cpp

@@ -1304,8 +1304,30 @@ static void lua_module_reader(deserializer & d, module_idx, shared_environment &
 void parser::parse_imports() {
     buffer<module_name> olean_files;
     buffer<name>        lua_files;
+    bool prelude     = false;
     std::string base = dirname(get_stream_name().c_str());
     bool imported    = false;
+    if (curr_is_token(get_prelude_tk())) {
+        next();
+        prelude = true;
+    }
+    auto import_olean = [&](optional<unsigned> const & k, name const & f) {
+        if (auto it = try_file(base, k, f, ".olean")) {
+            olean_files.push_back(module_name(k, f));
+        } else {
+            m_found_errors = true;
+            if (!m_use_exceptions && m_show_errors) {
+                flycheck_error err(regular_stream());
+                display_error_pos(pos());
+                regular_stream() << " invalid import, unknown module '" << f << "'" << endl;
+            }
+            if (m_use_exceptions)
+                throw parser_error(sstream() << "invalid import, unknown module '" << f << "'", pos());
+        }
+    };
+    if (!prelude) {
+        import_olean(optional<unsigned>(), "init");
+    }
     while (curr_is_token(get_import_tk())) {
         imported       = true;
         m_last_cmd_pos = pos();
@@ -1327,17 +1349,8 @@ void parser::parse_imports() {
                     throw parser_error(sstream() << "invalid import, failed to import '" << f
                                        << "', relative paths are not supported for .lua files", pos());
                 lua_files.push_back(f);
-            } else if (auto it = try_file(base, k, f, ".olean")) {
-                olean_files.push_back(module_name(k, f));
             } else {
-                m_found_errors = true;
+                import_olean(k, f);
-                if (!m_use_exceptions && m_show_errors) {
-                    flycheck_error err(regular_stream());
-                    display_error_pos(pos());
-                    regular_stream() << " invalid import, unknown module '" << f << "'" << endl;
-                }
-                if (m_use_exceptions)
-                    throw parser_error(sstream() << "invalid import, unknown module '" << f << "'", pos());
             }
             next();
         }

src/frontends/lean/token_table.cpp

@@ -82,8 +82,8 @@ void init_token_table(token_table & t) {
         {"theorem", "axiom", "variable", "protected", "private", "opaque", "definition", "example", "coercion",
          "variables", "parameter", "parameters", "constant", "constants", "[persistent]", "[visible]", "[instance]",
          "[off]", "[on]", "[none]", "[class]", "[coercion]", "[reducible]", "[parsing-only]", "reducible", "irreducible",
-         "evaluate", "check", "eval", "[whnf]", "[strict]", "[local]", "[priority", "print", "end", "namespace", "section", "import",
+         "evaluate", "check", "eval", "[whnf]", "[strict]", "[local]", "[priority", "print", "end", "namespace", "section", "prelude",
-         "inductive", "record", "structure", "module", "universe", "universes",
+         "import", "inductive", "record", "structure", "module", "universe", "universes",
          "precedence", "reserve", "infixl", "infixr", "infix", "postfix", "prefix", "notation", "context",
          "exit", "set_option", "open", "export", "calc_subst", "calc_refl", "calc_trans", "calc_symm", "tactic_hint",
          "add_begin_end_tactic", "set_begin_end_tactic", "instance", "class", "find_decl",

src/frontends/lean/tokens.cpp

@@ -27,6 +27,7 @@ static name * g_max          = nullptr;
 static name * g_imax         = nullptr;
 static name * g_cup          = nullptr;
 static name * g_import       = nullptr;
+static name * g_prelude      = nullptr;
 static name * g_show         = nullptr;
 static name * g_have         = nullptr;
 static name * g_assume       = nullptr;
@@ -118,6 +119,7 @@ void initialize_tokens() {
     g_imax         = new name("imax");
     g_cup          = new name("\u2294");
     g_import       = new name("import");
+    g_prelude      = new name("prelude");
     g_show         = new name("show");
     g_have         = new name("have");
     g_assume       = new name("assume");
@@ -260,6 +262,7 @@ void finalize_tokens() {
     delete g_have;
     delete g_show;
     delete g_import;
+    delete g_prelude;
     delete g_cup;
     delete g_imax;
     delete g_max;
@@ -301,6 +304,7 @@ name const & get_max_tk() { return *g_max; }
 name const & get_imax_tk() { return *g_imax; }
 name const & get_cup_tk() { return *g_cup; }
 name const & get_import_tk() { return *g_import; }
+name const & get_prelude_tk() { return *g_prelude; }
 name const & get_show_tk() { return *g_show; }
 name const & get_have_tk() { return *g_have; }
 name const & get_assume_tk() { return *g_assume; }

src/frontends/lean/tokens.h

@@ -29,6 +29,7 @@ name const & get_max_tk();
 name const & get_imax_tk();
 name const & get_cup_tk();
 name const & get_import_tk();
+name const & get_prelude_tk();
 name const & get_show_tk();
 name const & get_have_tk();
 name const & get_assume_tk();