1 files changed, 82 insertions, 0 deletions

diff --git a/src/scriptengine.cpp b/src/scriptengine.cpp
new file mode 100644
index 0000000..7b5df03
--- /dev/null
+++ b/src/scriptengine.cpp
@@ -0,0 +1,82 @@
+#include "scriptengine.h"
+#include "lexer.h"
+#include "parser.h"
+#include "expression.h"
+
+#include <bu/staticmembuf.h>
+#include <bu/exceptionbase.h>
+
+ScriptEngine::ScriptEngine()
+{
+}
+
+ScriptEngine::~ScriptEngine()
+{
+}
+
+Number ScriptEngine::exec( const Bu::String &sExpr )
+{
+    Bu::StaticMemBuf mb( sExpr.getStr(), sExpr.getSize() );
+    return exec( sExpr );
+}
+
+Number ScriptEngine::exec( Bu::Stream &sInput )
+{
+    Lexer l( sInput );
+    Parser p( l );
+    Expression *pExp = p.parse();
+    Number n = exec( pExp );
+    delete pExp;
+    return n;
+}
+
+Number ScriptEngine::exec( Expression *pExpr )
+{
+    NumStack sNums;
+
+    for( Expression::iterator i = pExpr->begin(); i; i++ )
+    {
+        switch( (*i).eType )
+        {
+            case Token::tNumber:
+                sNums.push( *(*i).nVal );
+                break;
+
+            case Token::tVariable:
+                if( hVarState.has( *(*i).sVal ) )
+                {
+                    sNums.push( hVarState[*(*i).sVal] );
+                }
+                else
+                {
+                    throw Bu::ExceptionBase(
+                        Bu::String("No such variable: $%1").arg(*(*i).sVal).end().getStr()
+                        );
+                }
+                break;
+
+            case Token::tPlus:
+                sNums.push( sNums.peekPop() + sNums.peekPop() );
+                break;
+
+            case Token::tMinus:
+                sNums.push( sNums.peekPop() - sNums.peekPop() );
+                break;
+
+            case Token::tDivide:
+                sNums.push( sNums.peekPop() / sNums.peekPop() );
+                break;
+
+            case Token::tMultiply:
+                sNums.push( sNums.peekPop() * sNums.peekPop() );
+                break;
+
+            case Token::tNegate:
+                sNums.push( -sNums.peekPop() );
+                break;
+        }
+    }
+
+    return sNums.peekPop();
+}
+