From 36384e69a5010ffc2d334a7fc4271f8c8cecad9f Mon Sep 17 00:00:00 2001
From: yhirose <yuji.hirose.bug@gmail.com>
Date: Wed, 3 Jun 2015 22:50:00 -0400
Subject: [PATCH] Added unary plus/minus/not operators.

---
 language/interpreter.cc | 27 +++++++++++++++++++++++++++
 language/parser.cc      | 17 +++++++++++++++--
 language/parser.hpp     |  2 +-
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/language/interpreter.cc b/language/interpreter.cc
index 9f5e36e..05fda22 100644
--- a/language/interpreter.cc
+++ b/language/interpreter.cc
@@ -18,6 +18,9 @@ struct Eval
             case LogicalOr:          return eval_logical_or(ast, env);
             case LogicalAnd:         return eval_logical_and(ast, env);
             case Condition:          return eval_condition(ast, env);
+            case UnaryPlus:          return eval_unary_plus(ast, env);
+            case UnaryMinus:         return eval_unary_minus(ast, env);
+            case UnaryNot:           return eval_unary_not(ast, env);
             case BinExpresion:       return eval_bin_expression(ast, env);
             case Identifier:         return eval_identifier(ast, env);
             case Number:             return eval_number(ast, env);
@@ -173,6 +176,30 @@ private:
         }
     }
 
+    static Value eval_unary_plus(const Ast& ast, shared_ptr<Environment> env) {
+        if (ast.nodes.size() == 1) {
+            return eval(*ast.nodes[0], env);
+        } else {
+            return eval(*ast.nodes[1], env);
+        }
+    }
+
+    static Value eval_unary_minus(const Ast& ast, shared_ptr<Environment> env) {
+        if (ast.nodes.size() == 1) {
+            return eval(*ast.nodes[0], env);
+        } else {
+            return Value(eval(*ast.nodes[1], env).to_long() * -1);
+        }
+    }
+
+    static Value eval_unary_not(const Ast& ast, shared_ptr<Environment> env) {
+        if (ast.nodes.size() == 1) {
+            return eval(*ast.nodes[0], env);
+        } else {
+            return Value(!eval(*ast.nodes[1], env).to_bool());
+        }
+    }
+
     static Value eval_bin_expression(const Ast& ast, shared_ptr<Environment> env) {
         auto ret = eval(*ast.nodes[0], env).to_long();
         for (auto i = 1u; i < ast.nodes.size(); i += 2) {
diff --git a/language/parser.cc b/language/parser.cc
index b8ad7a7..ce8ae4c 100644
--- a/language/parser.cc
+++ b/language/parser.cc
@@ -22,14 +22,21 @@ static auto g_grammar = R"(
     LOGICAL_OR            <-  LOGICAL_AND ('&&' _  LOGICAL_AND)*
     LOGICAL_AND           <-  CONDITION (CONDITION_OPERATOR CONDITION)*
     CONDITION             <-  TERM (TERM_OPERATOR TERM)*
-    TERM                  <-  FACTOR (FACTOR_OPERATOR FACTOR)*
+    TERM                  <-  UNARY_PLUS_OPERATOR? UNARY_PLUS
+    UNARY_PLUS            <-  UNARY_MINUS_OPERATOR? UNARY_MINUS
+    UNARY_MINUS           <-  UNARY_NOT_OPERATOR? UNARY_NOT
+    UNARY_NOT             <-  FACTOR (FACTOR_OPERATOR FACTOR)*
     FACTOR                <-  WHILE / IF / FUNCTION / FUNCTION_CALL / NUMBER / BOOLEAN / STRING / INTERPOLATED_STRING / IDENTIFIER / '(' _ EXPRESSION ')' _
 
     BLOCK                 <-  '{' _ STATEMENTS '}' _
 
     CONDITION_OPERATOR    <-  < ('==' / '!=' / '<=' / '<' / '>=' / '>') > _
     TERM_OPERATOR         <-  < [-+] > _
+    UNARY_PLUS_OPERATOR   <-  < '+' > _
+    UNARY_MINUS_OPERATOR  <-  < '-' > _
+    UNARY_NOT_OPERATOR    <-  < '!' > _
     FACTOR_OPERATOR       <-  < [*/%] > _
+
     IDENTIFIER            <-  < [a-zA-Z_][a-zA-Z0-9_]* > _
 
     NUMBER                <-  < [0-9]+ > _
@@ -78,9 +85,15 @@ peg& get_parser()
             { peg::AstNodeType::Optimizable, "LOGICAL_OR",           LogicalAnd         },
             { peg::AstNodeType::Optimizable, "LOGICAL_AND",          Condition          },
             { peg::AstNodeType::Optimizable, "CONDITION",            BinExpresion       },
-            { peg::AstNodeType::Optimizable, "TERM",                 BinExpresion       },
+            { peg::AstNodeType::Optimizable, "TERM",                 UnaryPlus          },
+            { peg::AstNodeType::Optimizable, "UNARY_PLUS",           UnaryMinus         },
+            { peg::AstNodeType::Optimizable, "UNARY_MINUS",          UnaryNot           },
+            { peg::AstNodeType::Optimizable, "UNARY_NOT",            BinExpresion       },
             { peg::AstNodeType::Token,       "CONDITION_OPERATOR",   Undefined          },
             { peg::AstNodeType::Token,       "TERM_OPERATOR",        Undefined          },
+            { peg::AstNodeType::Token,       "UNARY_PLUS_OPERATOR",  Undefined          },
+            { peg::AstNodeType::Token,       "UNARY_MINUS_OPERATOR", Undefined          },
+            { peg::AstNodeType::Token,       "UNARY_NOT_OPERATOR",   Undefined          },
             { peg::AstNodeType::Token,       "FACTOR_OPERATOR",      Undefined          },
             { peg::AstNodeType::Token,       "NUMBER",               Number             },
             { peg::AstNodeType::Token,       "BOOLEAN",              Boolean            },
diff --git a/language/parser.hpp b/language/parser.hpp
index 083e86e..8b9335a 100644
--- a/language/parser.hpp
+++ b/language/parser.hpp
@@ -4,7 +4,7 @@ enum AstTag
 {
    Undefined,
    Statements, While, If, FunctionCall, Assignment,
-   LogicalOr, LogicalAnd, Condition, BinExpresion,
+   LogicalOr, LogicalAnd, Condition, UnaryPlus, UnaryMinus, UnaryNot, BinExpresion,
    Identifier, InterpolatedString,
    Number, Boolean, Function
 };