9 files changed, 155 insertions, 9 deletions

diff --git a/src/lexer.cpp b/src/lexer.cpp
index b0d0fd1..fbcaafb 100644
--- a/src/lexer.cpp
+++ b/src/lexer.cpp
@@ -11,27 +11,55 @@ Lexer::Lexer( Bu::Stream &rIn ) :
     iRadix( 10 ),

     numRangeTop('9'),

     ascRangeTop('a'-1),

-    eMode( modeNormal )

+    eMode( modeNormal ),

+    iLookAheadSize( 2 ),

+    iLookAheadUsed( 0 ),

+    iLookAheadStart( 0 ),

+    aLookAhead( 0 )

 {

+    aLookAhead = new Token[iLookAheadSize];

 }

 

 Lexer::~Lexer()

 {

 }

 

-Token Lexer::nextToken()

+void Lexer::nextToken()

+{

+    if( iLookAheadSize <= 1 )

+    {

+        iLookAheadSize = 0;

+        iLookAheadStart = 0;

+    }

+    else

+    {

+        iLookAheadStart = (iLookAheadStart+1)%iLookAheadSize;

+        iLookAheadSize--;

+    }

+}

+

+void Lexer::fillToken()

 {

     switch( eMode )

     {

         case modeNormal:

-            return nextTokenNormal();

+            aLookAhead[(iLookAheadUsed+iLookAheadStart)%iLookAheadSize] =

+                nextTokenNormal();

+            break;

 

         case modeCommand:

-            return nextTokenCommand();

+            aLookAhead[(iLookAheadUsed+iLookAheadStart)%iLookAheadSize] =

+                nextTokenCommand();

+            break;

 

         default:

             throw Bu::ExceptionBase("Invalid mode.");

     }

+

+    Bu::sio << "read["

+        << ((iLookAheadUsed+iLookAheadStart)%iLookAheadSize)

+        << "]: "

+        << aLookAhead[(iLookAheadUsed+iLookAheadStart)%iLookAheadSize].eType;

 }

 

 Token Lexer::nextTokenNormal()

@@ -235,5 +263,11 @@ void Lexer::setRadix( int i )
 

 Token &Lexer::operator[]( int iIdx )

 {

+    while( iIdx >= iLookAheadUsed )

+    {

+        fillToken();

+        iLookAheadUsed++;

+    }

+    return aLookAhead[(iLookAheadStart+iIdx)%iLookAheadSize];

 }

 

diff --git a/src/lexer.h b/src/lexer.h
index d5631d4..193a22b 100644
--- a/src/lexer.h
+++ b/src/lexer.h
@@ -20,7 +20,7 @@ public:
     void setMode( Mode e ) { eMode = e; }

     Mode getMode() const { return eMode; }

 

-    Token nextToken();

+    void nextToken();

 

     int getScale() const { return iScale; }

     void setScale( int i ) { iScale = i; }

@@ -31,6 +31,7 @@ public:
     Token &operator[]( int iIdx );

 

 private:

+    void fillToken();

     Token nextTokenNormal();

     Token nextTokenCommand();

 

@@ -43,6 +44,11 @@ private:
     char numRangeTop;

     char ascRangeTop;

     Mode eMode;

+

+    int iLookAheadSize;

+    int iLookAheadUsed;

+    int iLookAheadStart;

+    Token *aLookAhead;

 };

 

 #endif

diff --git a/src/options.cpp b/src/options.cpp
index c127022..3c016a6 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -191,7 +191,7 @@ int Options::execute( Bu::StringArray aArgs )
         mbIn.write(" ");

         mbIn.write( aArgs[j] );

     }

-//    Bu::println("eq: '''%1'''").arg( mbIn.getString() );

+    Bu::println("eq: '''%1'''").arg( mbIn.getString() );

     mbIn.setPos( 0 );

     Bu::MemBuf mbOut;

     Lexer lex( mbIn );

diff --git a/src/parser.cpp b/src/parser.cpp
index 153b6fe..1f9a193 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -22,6 +22,58 @@ void Parser::parse()
 {

     for(;;)

     {

+        lex.nextToken();

+        expr();

+

+        for( TokenStack::iterator i = tsStack.begin(); i; i++ )

+        {

+            Bu::sio << *i << " ";

+        }

+    }

+}

+

+void Parser::expr()

+{

+    if( lex[0].eType == Token::tVariable &&

+        lex[1].eType == Token::tEquals )

+    {

+        // Assignment!

+        expr();

+        return;

+    }

+    exprP();

+}

+

+void Parser::exprP()

+{

+    switch( lex[0].eType )

+    {

+        case Token::tNumber:

+        case Token::tVariable:

+            tsStack.push( lex[0] );

+            lex.nextToken();

+            break;

+

+        case Token::tOpenParen:

+            lex.nextToken();

+            expr();

+            if( lex[0].eType != Token::tCloseParen )

+            {

+                throw Bu::ExceptionBase("Expected close paren");

+            }

+            lex.nextToken();

+            break;

+

+        case Token::tMinus:

+            lex.nextToken();

+            exprP();

+            tsStack.push( Token( Token::tNegate ) );            

+            break;

+    }

+}

+/*

+    for(;;)

+    {

         Token t = lex.nextToken();

         switch( t.eType )

         {

@@ -158,6 +210,7 @@ void Parser::parse()
         }

     }

 }

+*/

 

 Number Parser::getVariable( const Bu::String &sName )

 {

@@ -171,6 +224,7 @@ void Parser::setVariable( const Bu::String &sName, const Number &rValue )
 

 void Parser::unwind()

 {

+    /*

     for(;;)

     {

         DBS_START( PARSE );

@@ -312,6 +366,7 @@ void Parser::unwind()
             getPriority( t.eType ) )

             return;

     }

+    */

 }

 

 int Parser::reqTokens( Token::Type eType )

diff --git a/src/parser.h b/src/parser.h
index e163212..d50951b 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -13,6 +13,35 @@ namespace Bu
 

 class Lexer;

 

+/**

+ *

+ * expr: literal

+ *     | variable

+ *     | expr '+' expr

+ *     | expr '-' expr

+ *     | expr '*' expr

+ *     | expr '/' expr

+ *     | '(' expr ')'

+ *     | '-' expr

+ *     | variable '=' expr

+ *     ;

+ *

+ * -----

+ * 

+ * expr': literal

+ *      | variable

+ *      | '(' expr ')'

+ *      | '-' expr'

+ *      ;

+ *

+ * expr: expr' '+' expr

+ *     | expr' '-' expr

+ *     | expr' '*' expr

+ *     | expr' '/' expr

+ *     | expr'

+ *     | variable '=' expr

+ *     ;

+ */

 class Parser

 {

 public:

@@ -24,6 +53,10 @@ public:
     void setVariable( const Bu::String &sName, const Number &rValue );

 

 private:

+    void expr();

+    void exprP();

+

+private:

     void unwind();

     int reqTokens( Token::Type eType );

     int getPriority( Token::Type eType );

@@ -34,8 +67,8 @@ private:
     Bu::Stream &rOut;

     typedef Bu::List<Token> TokenStack;

     typedef Bu::Hash<Bu::String, Number> VarHash;

-    TokenStack tsTerminal;

-    TokenStack tsNonTerminal;

+    TokenStack tsStack;

+//    TokenStack tsNonTerminal;

     Number nZero;

     VarHash hVars;

 };

diff --git a/src/token.cpp b/src/token.cpp
index a03c821..30f3566 100644
--- a/src/token.cpp
+++ b/src/token.cpp
@@ -4,6 +4,12 @@
 #include <bu/formatter.h>

 #include <bu/string.h>

 

+Token::Token() :

+    eType( tUninitialized ),

+    sVal( 0 )

+{

+}

+

 Token::Token( Type eType ) :

     eType( eType ),

     sVal( 0 )

diff --git a/src/token.h b/src/token.h
index 92a7bcc..12a4904 100644
--- a/src/token.h
+++ b/src/token.h
@@ -26,11 +26,15 @@ public:
         tEquals,

         tString,

 

+        tNegate,

         tEndOfLine,

 

-        tEndOfInput

+        tEndOfInput,

+

+        tUninitialized

     };

 

+    Token();

     Token( Type eType );

     Token( Type eType, Bu::String *s );

     Token( Type eType, Number *n );

diff --git a/src/unitparser.cpp b/src/unitparser.cpp
index f518fdc..09b5982 100644
--- a/src/unitparser.cpp
+++ b/src/unitparser.cpp
@@ -13,6 +13,8 @@ UnitParser::UnitParser()
             "order1", Bu::UnitSuite::expectPass );

     add( static_cast<Bu::UnitSuite::Test>(&UnitParser::assignment),

             "assignment", Bu::UnitSuite::expectPass );

+    add( static_cast<Bu::UnitSuite::Test>(&UnitParser::parse1),

+            "parse1", Bu::UnitSuite::expectPass );

 }

 

 UnitParser::~UnitParser()

@@ -55,3 +57,8 @@ void UnitParser::assignment()
     unitTest( mbOut.getString().trimWhitespace() == parser.getVariable("test").toString() );

 }

 

+void UnitParser::parse1()

+{

+    unitTest(parse("-5") == "-5");

+}

+

diff --git a/src/unitparser.h b/src/unitparser.h
index 744deef..c3b3687 100644
--- a/src/unitparser.h
+++ b/src/unitparser.h
@@ -11,6 +11,7 @@ public:
 

     void order1();

     void assignment();

+    void parse1();

 };

 

 #endif