Added initial support for lambda functions

6 files changed, 129 insertions, 27 deletions

diff --git a/src/op.cc b/src/op.cc
index 6105e38e..86057f66 100644
--- a/src/op.cc
+++ b/src/op.cc
@@ -108,10 +108,15 @@ expr_t::ptr_op_t expr_t::op_t::compile(scope_t& scope, const int depth)
       scope.define(symbol_t::FUNCTION, left()->as_ident(), right());
       break;
     case O_CALL:
-      if (left()->left()->is_ident())
-        scope.define(symbol_t::FUNCTION, left()->left()->as_ident(), this);
-      else
+      if (left()->left()->is_ident()) {
+        ptr_op_t node(new op_t(op_t::O_LAMBDA));
+        node->set_left(left()->right());
+        node->set_right(right());
+
+        scope.define(symbol_t::FUNCTION, left()->left()->as_ident(), node);
+      } else {
         throw_(compile_error, _("Invalid function definition"));
+      }
       break;
     default:
       throw_(compile_error, _("Invalid function definition"));
@@ -183,16 +188,12 @@ value_t expr_t::op_t::calc(scope_t& scope, ptr_op_t * locus, const int depth)
     break;
   }
 
-  case O_DEFINE: {
+  case O_LAMBDA: {
     call_scope_t&  call_args(downcast<call_scope_t>(scope));
-    std::size_t    args_count = call_args.size();
-    std::size_t    args_index = 0;
-
-    assert(left()->kind == O_CALL);
-
-    ptr_op_t sym = left()->right();
-
+    std::size_t    args_count(call_args.size());
+    std::size_t    args_index(0);
     symbol_scope_t call_scope(call_args);
+    ptr_op_t       sym(left());
 
     for (; sym; sym = sym->has_right() ? sym->right() : NULL) {
       ptr_op_t varname = sym;
@@ -618,6 +619,14 @@ bool expr_t::op_t::print(std::ostream& out, const context_t& context) const
       found = true;
     break;
 
+  case O_LAMBDA:
+    if (left() && left()->print(out, context))
+      found = true;
+    out << " -> ";
+    if (has_right() && right()->print(out, context))
+      found = true;
+    break;
+
   case O_CALL:
     if (left() && left()->print(out, context))
       found = true;
@@ -692,6 +701,7 @@ void expr_t::op_t::dump(std::ostream& out, const int depth) const
 
   case O_DEFINE: out << "O_DEFINE"; break;
   case O_LOOKUP: out << "O_LOOKUP"; break;
+  case O_LAMBDA: out << "O_LAMBDA"; break;
   case O_CALL:   out << "O_CALL"; break;
   case O_MATCH:  out << "O_MATCH"; break;
 
diff --git a/src/op.h b/src/op.h
index aa591b28..63d844bf 100644
--- a/src/op.h
+++ b/src/op.h
@@ -104,6 +104,7 @@ public:
 
     O_DEFINE,
     O_LOOKUP,
+    O_LAMBDA,
     O_CALL,
     O_MATCH,
 
diff --git a/src/parser.cc b/src/parser.cc
index a5b1e6e3..e9205d16 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -232,15 +232,12 @@ expr_t::parser_t::parse_logic_expr(std::istream& in,
 
   if (node && ! tflags.has_flags(PARSE_SINGLE)) {
     while (true) {
-      op_t::kind_t  kind         = op_t::LAST;
+      op_t::kind_t  kind   = op_t::LAST;
       parse_flags_t _flags = tflags;
-      token_t&    tok    = next_token(in, tflags.plus_flags(PARSE_OP_CONTEXT));
-      bool        negate = false;
+      token_t&      tok    = next_token(in, tflags.plus_flags(PARSE_OP_CONTEXT));
+      bool          negate = false;
 
       switch (tok.kind) {
-      case token_t::DEFINE:
-        kind = op_t::O_DEFINE;
-        break;
       case token_t::EQUAL:
         if (tflags.has_flags(PARSE_NO_ASSIGN))
           tok.rewind(in);
@@ -422,22 +419,42 @@ expr_t::parser_t::parse_querycolon_expr(std::istream& in,
 }
 
 expr_t::ptr_op_t
-expr_t::parser_t::parse_value_expr(std::istream& in,
-                                   const parse_flags_t& tflags) const
+expr_t::parser_t::parse_lambda_expr(std::istream& in,
+                                    const parse_flags_t& tflags) const
 {
   ptr_op_t node(parse_querycolon_expr(in, tflags));
 
   if (node && ! tflags.has_flags(PARSE_SINGLE)) {
+    token_t& tok = next_token(in, tflags.plus_flags(PARSE_OP_CONTEXT));
+
+    if (tok.kind == token_t::ARROW) {
+      ptr_op_t prev(node);
+      node = new op_t(op_t::O_LAMBDA);
+      node->set_left(prev);
+      node->set_right(parse_querycolon_expr(in, tflags));
+    } else {
+      push_token(tok);
+    }
+  }
+
+  return node;
+}
+
+expr_t::ptr_op_t
+expr_t::parser_t::parse_comma_expr(std::istream& in,
+                                   const parse_flags_t& tflags) const
+{
+  ptr_op_t node(parse_lambda_expr(in, tflags));
+
+  if (node && ! tflags.has_flags(PARSE_SINGLE)) {
     ptr_op_t next;
     while (true) {
       token_t& tok = next_token(in, tflags.plus_flags(PARSE_OP_CONTEXT));
 
-      if (tok.kind == token_t::COMMA || tok.kind == token_t::SEMI) {
-        bool comma_op = tok.kind == token_t::COMMA;
-
+      if (tok.kind == token_t::COMMA) {
         if (! next) {
           ptr_op_t prev(node);
-          node = new op_t(comma_op ? op_t::O_CONS : op_t::O_SEQ);
+          node = new op_t(op_t::O_CONS);
           node->set_left(prev);
 
           next = node;
@@ -448,8 +465,65 @@ expr_t::parser_t::parse_value_expr(std::istream& in,
         if (ntok.kind == token_t::RPAREN)
           break;
 
-        ptr_op_t chain(new op_t(comma_op ? op_t::O_CONS : op_t::O_SEQ));
-        chain->set_left(parse_querycolon_expr(in, tflags));
+        ptr_op_t chain(new op_t(op_t::O_CONS));
+        chain->set_left(parse_lambda_expr(in, tflags));
+
+        next->set_right(chain);
+        next = chain;
+      } else {
+        push_token(tok);
+        break;
+      }
+    }
+  }
+
+  return node;
+}
+
+expr_t::ptr_op_t
+expr_t::parser_t::parse_assign_expr(std::istream& in,
+                                    const parse_flags_t& tflags) const
+{
+  ptr_op_t node(parse_comma_expr(in, tflags));
+
+  if (node && ! tflags.has_flags(PARSE_SINGLE)) {
+    token_t& tok = next_token(in, tflags.plus_flags(PARSE_OP_CONTEXT));
+
+    if (tok.kind == token_t::ASSIGN) {
+      ptr_op_t prev(node);
+      node = new op_t(op_t::O_DEFINE);
+      node->set_left(prev);
+      node->set_right(parse_comma_expr(in, tflags));
+    } else {
+      push_token(tok);
+    }
+  }
+
+  return node;
+}
+
+expr_t::ptr_op_t
+expr_t::parser_t::parse_value_expr(std::istream& in,
+                                   const parse_flags_t& tflags) const
+{
+  ptr_op_t node(parse_assign_expr(in, tflags));
+
+  if (node && ! tflags.has_flags(PARSE_SINGLE)) {
+    ptr_op_t next;
+    while (true) {
+      token_t& tok = next_token(in, tflags.plus_flags(PARSE_OP_CONTEXT));
+
+      if (tok.kind == token_t::SEMI) {
+        if (! next) {
+          ptr_op_t prev(node);
+          node = new op_t(op_t::O_SEQ);
+          node->set_left(prev);
+
+          next = node;
+        }
+
+        ptr_op_t chain(new op_t(op_t::O_SEQ));
+        chain->set_left(parse_assign_expr(in, tflags));
 
         next->set_right(chain);
         next = chain;
diff --git a/src/parser.h b/src/parser.h
index 93ea994f..9a65765d 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -93,6 +93,12 @@ class expr_t::parser_t : public noncopyable
                          const parse_flags_t& flags) const;
   ptr_op_t parse_querycolon_expr(std::istream& in,
                                  const parse_flags_t& flags) const;
+  ptr_op_t parse_comma_expr(std::istream& in,
+                            const parse_flags_t& flags) const;
+  ptr_op_t parse_lambda_expr(std::istream& in,
+                             const parse_flags_t& flags) const;
+  ptr_op_t parse_assign_expr(std::istream& in,
+                             const parse_flags_t& flags) const;
   ptr_op_t parse_value_expr(std::istream& in,
                             const parse_flags_t& flags) const;
 
diff --git a/src/token.cc b/src/token.cc
index be39205c..199c3b3c 100644
--- a/src/token.cc
+++ b/src/token.cc
@@ -269,6 +269,15 @@ void expr_t::token_t::next(std::istream& in, const parse_flags_t& pflags,
 
   case '-':
     in.get(c);
+    c = static_cast<char>(in.peek());
+    if (c == '>') {
+      in.get(c);
+      symbol[1] = c;
+      symbol[2] = '\0';
+      kind = ARROW;
+      length = 2;
+      break;
+    }
     kind = MINUS;
     break;
   case '+':
@@ -329,7 +338,7 @@ void expr_t::token_t::next(std::istream& in, const parse_flags_t& pflags,
       length = 2;
       break;
     }
-    kind = DEFINE;
+    kind = ASSIGN;
     break;
 
   case '<':
diff --git a/src/token.h b/src/token.h
index 28e29752..13a799cb 100644
--- a/src/token.h
+++ b/src/token.h
@@ -56,6 +56,8 @@ struct expr_t::token_t : public noncopyable
 
     LPAREN,                     // (
     RPAREN,                     // )
+    LBRACE,                     // {
+    RBRACE,                     // }
 
     EQUAL,                      // ==
     NEQUAL,                     // !=
@@ -64,7 +66,6 @@ struct expr_t::token_t : public noncopyable
     GREATER,                    // >
     GREATEREQ,                  // >=
 
-    DEFINE,                     // :=
     ASSIGN,                     // =
     MATCH,                      // =~
     NMATCH,                     // !~
@@ -72,6 +73,7 @@ struct expr_t::token_t : public noncopyable
     PLUS,                       // +
     STAR,                       // *
     SLASH,                      // /
+    ARROW,                      // ->
     KW_DIV,                     // div
 
     EXCLAM,                     // !, not