From bdca82ea66259de136ce9374e172f567ee93ef89 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Sat, 9 Jan 2016 00:37:48 -0700
Subject: [PATCH] implement pub const

---
 example/guess_number/main.zig |  4 ----
 src/analyze.cpp               | 23 +++++++++++++++++++++++
 src/parser.cpp                | 27 +++++++++++++++++++--------
 src/parser.hpp                |  1 +
 std/std.zig                   |  7 +++----
 5 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/example/guess_number/main.zig b/example/guess_number/main.zig
index 52578d0a00..12b7a53752 100644
--- a/example/guess_number/main.zig
+++ b/example/guess_number/main.zig
@@ -3,10 +3,6 @@ export executable "guess_number";
 use "std.zig";
 use "rand.zig";
 
-// TODO don't duplicate these; implement pub const
-const stdout_fileno : isize = 1;
-const stderr_fileno : isize = 2;
-
 pub fn main(argc: isize, argv: &&u8, env: &&u8) -> i32 {
     print_str("Welcome to the Guess Number Game in Zig.\n");
 
diff --git a/src/analyze.cpp b/src/analyze.cpp
index 141492689a..29729070af 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -2635,6 +2635,29 @@ static void analyze_top_level_declaration(CodeGen *g, ImportTableEntry *import,
                         }
                     }
                 }
+
+                // import all the public variables
+                {
+                    auto it = target_import->block_context->variable_table.entry_iterator();
+                    for (;;) {
+                        auto *entry = it.next();
+                        if (!entry)
+                            break;
+
+                        VariableTableEntry *var = entry->value;
+                        bool is_pub = (var->decl_node->data.variable_declaration.visib_mod != VisibModPrivate);
+                        if (is_pub) {
+                            auto existing_entry = import->type_table.maybe_get(entry->key);
+                            if (existing_entry) {
+                                add_node_error(g, node,
+                                    buf_sprintf("import of variable '%s' overrides existing definition",
+                                        buf_ptr(&var->name)));
+                            } else {
+                                import->block_context->variable_table.put(entry->key, entry->value);
+                            }
+                        }
+                    }
+                }
                 break;
             }
         case NodeTypeStructDecl:
diff --git a/src/parser.cpp b/src/parser.cpp
index 567d5a9c0c..a27f2d66d9 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -1965,23 +1965,34 @@ static AstNode *ast_parse_return_expr(ParseContext *pc, int *token_index, bool m
 VariableDeclaration : option(FnVisibleMod) (token(Var) | token(Const)) token(Symbol) (token(Eq) Expression | token(Colon) Type option(token(Eq) Expression))
 */
 static AstNode *ast_parse_variable_declaration_expr(ParseContext *pc, int *token_index, bool mandatory) {
-    Token *var_or_const_tok = &pc->tokens->at(*token_index);
+    Token *first_token = &pc->tokens->at(*token_index);
 
-    bool is_const;
-    if (var_or_const_tok->id == TokenIdKeywordVar) {
-        is_const = false;
-    } else if (var_or_const_tok->id == TokenIdKeywordConst) {
-        is_const = true;
+    VisibMod visib_mod;
+
+    if (first_token->id == TokenIdKeywordPub) {
+        *token_index += 1;
+        visib_mod = VisibModPub;
+    } else if (first_token->id == TokenIdKeywordExport) {
+        *token_index += 1;
+        visib_mod = VisibModExport;
+    } else if (first_token->id == TokenIdKeywordVar ||
+               first_token->id == TokenIdKeywordConst)
+    {
+        visib_mod = VisibModPrivate;
     } else if (mandatory) {
-        ast_invalid_token_error(pc, var_or_const_tok);
+        ast_invalid_token_error(pc, first_token);
     } else {
         return nullptr;
     }
 
+    Token *var_or_const_tok = &pc->tokens->at(*token_index);
+    bool is_const = (var_or_const_tok->id == TokenIdKeywordConst);
     *token_index += 1;
-    AstNode *node = ast_create_node(pc, NodeTypeVariableDeclaration, var_or_const_tok);
+
+    AstNode *node = ast_create_node(pc, NodeTypeVariableDeclaration, first_token);
 
     node->data.variable_declaration.is_const = is_const;
+    node->data.variable_declaration.visib_mod = visib_mod;
 
     Token *name_token = ast_eat_token(pc, token_index, TokenIdSymbol);
     ast_buf_from_token(pc, name_token, &node->data.variable_declaration.symbol);
diff --git a/src/parser.hpp b/src/parser.hpp
index 46ef69db02..43d8281657 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -126,6 +126,7 @@ struct AstNodeReturnExpr {
 struct AstNodeVariableDeclaration {
     Buf symbol;
     bool is_const;
+    VisibMod visib_mod;
     // one or both of type and expr will be non null
     AstNode *type;
     AstNode *expr;
diff --git a/std/std.zig b/std/std.zig
index 2ccacc3166..e1d669624f 100644
--- a/std/std.zig
+++ b/std/std.zig
@@ -1,8 +1,8 @@
 use "syscall.zig";
 
-const stdin_fileno : isize = 0;
-const stdout_fileno : isize = 1;
-const stderr_fileno : isize = 2;
+pub const stdin_fileno : isize = 0;
+pub const stdout_fileno : isize = 1;
+pub const stderr_fileno : isize = 2;
 
 // TODO error handling
 pub fn os_get_random_bytes(buf: &u8, count: usize) -> isize {
@@ -41,7 +41,6 @@ pub fn print_i64(x: i64) -> isize {
 
 // TODO error handling
 pub fn readline(buf: []u8, out_len: &usize) -> bool {
-    // TODO unknown size array indexing operator
     const amt_read = read(stdin_fileno, buf.ptr, buf.len);
     if (amt_read < 0) {
         return true;