ADD: variable declaration.

doc/grammar.bnf

@@ -1,2 +1,6 @@
 MODULE ::= EXPR*
-EXPR ::= bool
+EXPR ::=
+  bool
+| ident
+| VARDECL
+VARDECL ::= opar decl ident EXPR cpar

meson.build

@@ -24,6 +24,7 @@ grino_src = static_library('grino',
                              'src/Program.cpp',
                              'src/VM.cpp',
                              'src/Value.cpp',
+                             'src/SymTable.cpp',
                            ])
 
 grino_dep = declare_dependency(link_with: grino_src)

src/Compiler.cpp

@@ -1,10 +1,13 @@
 #include "Compiler.hpp"
 #include "Program.hpp"
+#include "SymTable.hpp"
+#include "src/opcodes.hpp"
 
 namespace grino
 {
-  /*explicit*/ Compiler::Compiler(Logger& logger)
+  /*explicit*/ Compiler::Compiler(Logger& logger, SymTable& sym)
     : m_logger { logger }
+    , m_sym { sym }
   {
   }
 
@@ -21,6 +24,7 @@ namespace grino
         for (size_t i=0; i<node->size(); i++)
           {
             compile(node->child(i).lock(), program);
+            program.push_instr(OPCODE_POP);
           }
       } break;
 
@@ -32,6 +36,31 @@ namespace grino
                            program.push_constant(value));
       } break;
 
+      case NODE_VARDECL: {
+        std::string ident = node->child(0).lock()->repr();
+        auto expr = node->child(1).lock();
+        size_t address = get_local_address();
+
+        compile(expr, program);
+
+        m_sym.declare(node->loc(), ident, address);
+        program.push_instr(OPCODE_STORE_LOCAL, address);
+      } break;
+
+      case NODE_IDENT: {
+        std::string ident = node->repr();
+        auto entry = m_sym.find(ident);
+
+        if (entry == std::nullopt)
+          {
+            std::stringstream ss;
+            ss << "undefined variable '" << ident << "'";
+            m_logger.log<compile_error>(LOG_ERROR, node->loc(), ss.str());
+          }
+
+        program.push_instr(OPCODE_LOAD_LOCAL, entry->addr);
+      } break;
+
       default:
         std::cerr << "cannot compile node '"
                   << GRINO_TRIM(NodeTypeStr[node->type()], "NODE_")
@@ -39,4 +68,11 @@ namespace grino
         abort();
       }
   }
+
+  size_t Compiler::get_local_address()
+  {
+    static size_t addr = 0;
+    addr++;
+    return addr - 1;
+  }
 }

src/Compiler.hpp

@@ -4,15 +4,19 @@
 #include "commons.hpp"
 #include "Logger.hpp"
 #include "Node.hpp"
+#include "src/mutils.hpp"
 
 namespace grino
 {
   class Program;
+  class SymTable;
+
+  GRINO_ERROR(compile_error);
 
   class Compiler
   {
   public:
-    explicit Compiler(Logger& logger);
+    explicit Compiler(Logger& logger, SymTable& sym);
     virtual ~Compiler();
 
     void compile(std::shared_ptr<Node> node,
@@ -20,6 +24,9 @@ namespace grino
 
   private:
     Logger& m_logger;
+    SymTable& m_sym;
+
+    size_t get_local_address();
   };
 }
 

src/Lexer.cpp

@@ -7,8 +7,14 @@ namespace grino
     : m_logger { logger }
     , m_loc {source_path, 1}
   {
+    add_text(NODE_OPAR, "(", false);
+    add_text(NODE_CPAR, ")", false);
+    add_text(NODE_DECL, "$", false);
+
     add_keyword(NODE_BOOL, "true", true);
     add_keyword(NODE_BOOL, "false", true);
+
+    m_scanners.push_back(std::bind(&Lexer::scan_ident, this));
   }
 
   /*virtual*/ Lexer::~Lexer()
@@ -125,6 +131,7 @@ namespace grino
                                    text, has_value));
     if (text.size() == 1)
       {
+        m_separators.push_back(text[0]);
       }
   }
 
@@ -141,7 +148,7 @@ namespace grino
                                            std::string const& text,
                                            bool has_value)
   {
-    if (!has_more(m_cursor + text.size()))
+    if (m_cursor + text.size() > m_source.size())
       {
         return std::nullopt;
       }
@@ -191,4 +198,28 @@ namespace grino
     };
   }
 
+  std::optional<ScanInfo> Lexer::scan_ident()
+  {
+    size_t cursor = m_cursor;
+
+    std::string repr;
+
+    while (has_more(cursor)
+           && !is_sep(cursor))
+      {
+        repr += at(cursor);
+        cursor++;
+      }
+
+    if (repr.empty() == false)
+      {
+        return ScanInfo {
+          cursor,
+          NODE_IDENT,
+          repr
+        };
+      }
+
+    return std::nullopt;
+  }
 }

src/Lexer.hpp

@@ -57,6 +57,7 @@ namespace grino
                                          std::string const& text,
                                          bool has_value);
 
+    std::optional<ScanInfo> scan_ident();
   };
 }
 

src/Node.hpp

@@ -6,7 +6,12 @@
 
 #define NODE_TYPE(G)                            \
   G(NODE_MODULE),                               \
-    G(NODE_BOOL),
+    G(NODE_BOOL),                               \
+    G(NODE_VARDECL),                            \
+    G(NODE_IDENT),                              \
+    G(NODE_OPAR),                               \
+    G(NODE_CPAR),                               \
+    G(NODE_DECL),
 
 namespace grino
 {

src/Parser.cpp

@@ -97,9 +97,15 @@ namespace grino
       }
   }
 
+  std::shared_ptr<Node> Parser::make_node(NodeType type,
+                                          std::string const& repr)
+  {
+    return std::make_shared<Node>(type, repr, loc());
+  }
+
   std::shared_ptr<Node> Parser::parse_module()
   {
-    auto node = std::make_shared<Node>(NODE_MODULE, "", loc());
+    auto node = make_node(NODE_MODULE);
 
     while (m_cursor < m_tokens.size())
       {
@@ -111,7 +117,13 @@ namespace grino
 
   std::shared_ptr<Node> Parser::parse_expr()
   {
-    if (type_is(NODE_BOOL))
+    if (type_is(NODE_OPAR))
+      {
+        return parse_vardecl();
+      }
+
+    if (type_is(NODE_IDENT)
+        || type_is(NODE_BOOL))
       {
         return consume();
       }
@@ -126,4 +138,17 @@ namespace grino
     return nullptr;
   }
 
+  std::shared_ptr<Node> Parser::parse_vardecl()
+  {
+    auto node = make_node(NODE_VARDECL);
+    consume(NODE_OPAR);
+    consume(NODE_DECL);
+
+    node->add_child(consume(NODE_IDENT));
+    node->add_child(parse_expr());
+
+    consume(NODE_CPAR);
+
+    return node;
+  }
 }

src/Parser.hpp

@@ -29,8 +29,12 @@ namespace grino
     bool type_is(std::vector<NodeType> const& types) const;
     Loc loc() const;
 
+    std::shared_ptr<Node> make_node(NodeType type,
+                                    std::string const& repr="");
+
     std::shared_ptr<Node> parse_module();
     std::shared_ptr<Node> parse_expr();
+    std::shared_ptr<Node> parse_vardecl();
   };
 }
 

src/SymTable.cpp

@@ -0,0 +1,55 @@
+#include "SymTable.hpp"
+
+namespace grino
+{
+  /*explicit*/ SymTable::SymTable(Logger& logger)
+    : m_logger { logger }
+  {
+  }
+
+  /*virtual*/ SymTable::~SymTable()
+  {
+  }
+
+  void SymTable::declare(Loc const& loc, std::string const& name, size_t addr)
+  {
+    if (find(name))
+      {
+        m_logger.log<symbolic_error>(LOG_ERROR, loc, "'"
+                                     + name
+                                     + "' already defined");
+      }
+
+    SymEntry entry;
+    entry.addr = addr;
+    entry.name = name;
+    entry.is_global = false;
+
+    m_entries.push_back(entry);
+  }
+
+  std::optional<SymEntry> SymTable::find(std::string const& name)
+  {
+    for (size_t i=0; i<m_entries.size(); i++)
+      {
+        if (m_entries[i].name == name)
+          {
+            return m_entries[i];
+          }
+      }
+
+    return std::nullopt;
+  }
+
+  std::string SymTable::string() const
+  {
+    std::stringstream ss;
+
+    for (auto const& entry: m_entries)
+      {
+        ss << entry.addr << "\t" << entry.name << "\n";
+      }
+
+    return ss.str();
+  }
+}

src/SymTable.hpp

@@ -0,0 +1,34 @@
+#ifndef grino_SYMTABLE_HPP
+#define grino_SYMTABLE_HPP
+
+#include "commons.hpp"
+#include "Logger.hpp"
+
+namespace grino
+{
+  struct SymEntry {
+    std::string name;
+    bool is_global;
+    size_t addr;
+  };
+
+  GRINO_ERROR(symbolic_error);
+
+  class SymTable
+  {
+  public:
+    explicit SymTable(Logger& logger);
+    virtual ~SymTable();
+
+    void declare(Loc const& loc, std::string const& name, size_t addr);
+    std::optional<SymEntry> find(std::string const& name);
+
+    std::string string() const;
+
+  private:
+    Logger& m_logger;
+    std::vector<SymEntry> m_entries;
+  };
+}
+
+#endif

src/VM.cpp

@@ -6,6 +6,7 @@ namespace grino
   /*explicit*/ VM::VM(Logger& logger)
     : m_logger { logger }
   {
+    m_frames.push_back(Frame {});
   }
 
   /*virtual*/ VM::~VM()
@@ -29,6 +30,24 @@ namespace grino
             m_pc++;
           } break;
 
+          case OPCODE_POP: {
+            pop();
+            m_pc++;
+          } break;
+
+          case OPCODE_STORE_LOCAL: {
+            size_t addr = *instr.param;
+            auto value = program.constant(top());
+            set_local(addr, value);
+            m_pc++;
+          } break;
+
+          case OPCODE_LOAD_LOCAL: {
+            size_t addr = *instr.param;
+            push(program.push_constant(local(addr)));
+            m_pc++;
+          } break;
+
           default:
             std::cerr << "cannot execute unknown opcode "
                       << OpcodeTypeStr[instr.opcode]
@@ -72,4 +91,22 @@ namespace grino
 
     return addr;
   }
+
+  size_t VM::top()
+  {
+    size_t addr = m_stack[m_sp - 1];
+    return addr;
+  }
+
+  std::shared_ptr<Value> VM::local(size_t addr) const
+  {
+    return m_frames.back().locals.at(addr);
+  }
+
+  void VM::set_local(size_t addr,
+                     std::shared_ptr<Value> value)
+  {
+    m_frames.back().locals[addr] = value;
+  }
+
 }

src/VM.hpp

@@ -11,6 +11,10 @@ namespace grino
 
   GRINO_ERROR(execution_error);
 
+  struct Frame {
+    std::unordered_map<size_t, std::shared_ptr<Value>> locals;
+  };
+
   class VM
   {
   public:
@@ -23,6 +27,7 @@ namespace grino
   private:
     Logger& m_logger;
     std::array<size_t, STACK_SIZE> m_stack;
+    std::vector<Frame> m_frames;
 
     size_t m_sp; /* stack pointer */
     size_t m_bp; /* base pointer */
@@ -30,6 +35,10 @@ namespace grino
 
     void push(size_t addr);
     size_t pop();
+    size_t top();
+    std::shared_ptr<Value> local(size_t addr) const;
+    void set_local(size_t addr,
+                   std::shared_ptr<Value> value);
   };
 }
 

src/main.cpp

@@ -8,6 +8,7 @@
 #include "Program.hpp"
 #include "VM.hpp"
 #include "Logger.hpp"
+#include "src/SymTable.hpp"
 
 int main(int argc, char** argv)
 {
@@ -73,8 +74,9 @@ int main(int argc, char** argv)
           std::cout << "--- ast ---" << std::endl;
           std::cout << ast->string() << std::endl;
         }
+      grino::SymTable sym_table {logger};
 
-      grino::Compiler compiler {logger};
+      grino::Compiler compiler {logger, sym_table};
       grino::Program program;
       compiler.compile(ast, program);
 

src/opcodes.hpp

@@ -5,7 +5,10 @@
 #include "src/mutils.hpp"
 
 #define OPCODES(G)                              \
-  G(OPCODE_LOAD_CONST)
+  G(OPCODE_LOAD_CONST),                         \
+    G(OPCODE_POP),                              \
+    G(OPCODE_LOAD_LOCAL),                       \
+    G(OPCODE_STORE_LOCAL)
 
 namespace grino
 {

tests/Lexer.cpp

@@ -24,13 +24,6 @@ protected:
   grino::Logger m_logger;
 };
 
-TEST_CASE_METHOD(LexerTest, "Lexer_errors")
-{
-  grino::Lexer lexer {m_logger, "tests/lexer"};
-  lexer.scan(" § ");
-  REQUIRE_THROWS_AS(lexer.next(), grino::lexical_error);
-}
-
 TEST_CASE_METHOD(LexerTest, "Lexer_booleans")
 {
   grino::Lexer lexer {m_logger, "tests/lexer"};
@@ -62,3 +55,25 @@ TEST_CASE_METHOD(LexerTest, "Lexer_comments")
   test_end(lexer);
 
 }
+
+TEST_CASE_METHOD(LexerTest, "Lexer_vardecl")
+{
+  grino::Lexer lexer {m_logger, "tests/lexer"};
+
+  lexer.scan(" $ () coucou) ");
+  test_next(lexer, "DECL");
+  test_next(lexer, "OPAR");
+  test_next(lexer, "CPAR");
+  test_next(lexer, "IDENT[coucou]");
+  test_next(lexer, "CPAR");
+  test_end(lexer);
+}
+
+TEST_CASE_METHOD(LexerTest, "Lexer_no_end_space")
+{
+  grino::Lexer lexer {m_logger, "tests/lexer"};
+
+  lexer.scan(")");
+  test_next(lexer, "CPAR");
+  test_end(lexer);
+}

tests/Parser.cpp

@@ -10,14 +10,15 @@ public:
 
   void test_parse(std::string const& oracle, std::string const& source)
   {
-    auto root = m_parser.parse(source);
+    grino::Logger logger;
+    grino::Lexer lexer {logger, "tests/parser"};
+    grino::Parser parser {logger, lexer};
+
+    auto root = parser.parse(source);
     REQUIRE(oracle == root->string());
   }
 
 protected:
-  grino::Logger m_logger;
-  grino::Lexer m_lexer {m_logger, "tests/parser"};
-  grino::Parser m_parser {m_logger, m_lexer};
 };
 
 TEST_CASE_METHOD(ParserTest, "Parser_empty")
@@ -29,3 +30,12 @@ TEST_CASE_METHOD(ParserTest, "Parser_booleans")
 {
   test_parse("MODULE(BOOL[true],BOOL[false])", "true false");
 }
+
+TEST_CASE_METHOD(ParserTest, "Parser_vardecl")
+{
+  test_parse("MODULE(VARDECL(IDENT[hello],BOOL[false]))",
+             "($ hello false)");
+
+  test_parse("MODULE(VARDECL(IDENT[hello],IDENT[world]))",
+             "($ hello world)");
+}