From 2909f50d008920568f0e50da760b266388ccc124 Mon Sep 17 00:00:00 2001
From: Mike Buland <mike@xagasoft.com>
Date: Mon, 22 Apr 2013 13:05:22 -0600
Subject: There is now a parser & calculator interface.

---
 src/lexer.cpp | 163 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 src/lexer.cpp

(limited to 'src/lexer.cpp')

diff --git a/src/lexer.cpp b/src/lexer.cpp
new file mode 100644
index 0000000..834d3bc
--- /dev/null
+++ b/src/lexer.cpp
@@ -0,0 +1,163 @@
+#include "lexer.h"
+#include "token.h"
+#include "number.h"
+
+#include <bu/sio.h>
+
+Lexer::Lexer( Bu::Stream &rIn ) :
+    rIn( rIn ),
+    iBufPos( 0 ),
+    iScale( 0 ),
+    iRadix( 10 ),
+    numRangeTop('9'),
+    ascRangeTop(0)
+{
+}
+
+Lexer::~Lexer()
+{
+}
+
+Token Lexer::nextToken()
+{
+    for(;;)
+    {
+        if( iBufPos >= sBuf.getSize() )
+        {
+            iBufPos = -1;
+            return Token( Token::tEndOfLine );
+        }
+
+        if( iBufPos < 0 )
+        {
+            if( rIn.isEos() )
+                return Token( Token::tEndOfInput );
+
+            sBuf = rIn.readLine();
+            if( sBuf.getSize() == 0 )
+            {
+                iBufPos = -1;
+                continue;
+            }
+            iBufPos = 0;
+        }
+
+        //Bu::println("Testing char '%1' at %2").arg( sBuf[iBufPos] ).arg( iBufPos );
+        switch( sBuf[iBufPos] )
+        {
+            case ' ':
+            case '\t':
+                iBufPos++;
+                break;
+
+            case '\\':
+                {
+                    Bu::String *sTmp = new Bu::String();
+                    for( iBufPos++; iBufPos < sBuf.getSize() &&
+                         sBuf[iBufPos] != ' ' && sBuf[iBufPos] != '\t';
+                         iBufPos++ )
+                    {
+                        sTmp->append( sBuf[iBufPos] );
+                    }
+                    return Token( Token::tCommand, sTmp );
+                }
+                break;
+
+            case '+':
+                iBufPos++;
+                return Token( Token::tPlus );
+
+            case '-':
+                iBufPos++;
+                return Token( Token::tMinus );
+
+            case '*':
+                iBufPos++;
+                return Token( Token::tMultiply );
+
+            case '/':
+                iBufPos++;
+                return Token( Token::tDivide );
+
+            case '(':
+                iBufPos++;
+                return Token( Token::tOpenParen );
+
+            case ')':
+                iBufPos++;
+                return Token( Token::tCloseParen );
+
+            default:
+                {
+                    Bu::String *sTmp = new Bu::String();
+                    if( (sBuf[iBufPos] >= '0' &&
+                                sBuf[iBufPos] <= numRangeTop) ||
+                        (sBuf[iBufPos] >= 'a' &&
+                                sBuf[iBufPos] <= ascRangeTop) ||
+                        sBuf[iBufPos] == '.' )
+                    {
+                        for( ; iBufPos < sBuf.getSize() ; iBufPos++ )
+                        {
+                            if( (sBuf[iBufPos] >= '0' &&
+                                        sBuf[iBufPos] <= numRangeTop) ||
+                                (sBuf[iBufPos] >= 'a' &&
+                                        sBuf[iBufPos] <= ascRangeTop) ||
+                                sBuf[iBufPos] == '.' )
+                            {
+                                sTmp->append( sBuf[iBufPos] );
+                            }
+                            else
+                            {
+                                break;
+                            }
+                        }
+                        Number *n = new Number( *sTmp, iScale, iRadix );
+                        delete sTmp;
+                        return Token( Token::tNumber, n );
+                    }
+                    else if( (sBuf[iBufPos]>=(ascRangeTop+1) && sBuf[iBufPos]<='z') ||
+                            (sBuf[iBufPos]>='A' && sBuf[iBufPos]<='Z') ||
+                            sBuf[iBufPos] == '_' )
+                    {
+                        for( ; iBufPos < sBuf.getSize(); iBufPos++ )
+                        {
+                            if( (sBuf[iBufPos]>='a' && sBuf[iBufPos]<='z') ||
+                                (sBuf[iBufPos]>='A' && sBuf[iBufPos]<='Z') ||
+                                (sBuf[iBufPos]>='0' && sBuf[iBufPos]<='9') ||
+                                sBuf[iBufPos] == '_' )
+                            {
+                                sTmp->append( sBuf[iBufPos] );
+                            }
+                            else
+                            {
+                                break;
+                            }
+                        }
+                        return Token( Token::tString, sTmp );
+                    }
+                    else
+                    {
+                        sBuf.clear();
+                        Bu::println("Invalid character discovered!");
+                    }
+                }
+                break;
+        }
+    }
+}
+
+void Lexer::setRadix( int i )
+{
+    iRadix = i;
+    if( iRadix <= 10 )
+    {
+        numRangeTop = '0'+iRadix-1;
+        ascRangeTop = 0;
+    }
+    else
+    {
+        numRangeTop = '9';
+        ascRangeTop = 'a'+iRadix-11;
+    }
+}
+
-- 
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