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#include "config.h"
#include "parser.h"
#include "lexer.h"
#include "number.h"
#include "datafiles.h"
#include <bu/sio.h>
#include <stdlib.h>
Parser::Parser( Lexer &lex, Bu::Stream &rOut ) :
lex( lex ),
rOut( rOut )
{
}
Parser::~Parser()
{
}
void Parser::parse()
{
for(;;)
{
Token t = lex.nextToken();
switch( t.eType )
{
case Token::tEndOfInput:
while( !tsNonTerminal.isEmpty() )
unwind();
return;
case Token::tEndOfLine:
while( !tsNonTerminal.isEmpty() )
unwind();
if( !tsTerminal.isEmpty() )
{
Bu::println( rOut, "%1").arg( deref( tsTerminal.peek() ) );
hVars.insert("ans", deref( tsTerminal.peek() ) );
}
tsTerminal.clear();
lex.setMode( Lexer::modeNormal );
break;
case Token::tCommand:
lex.setMode( Lexer::modeCommand );
if( *t.sVal == "exit" || *t.sVal == "quit" )
return;
else if( *t.sVal == "scale" )
{
Token t2 = lex.nextToken();
if( t2.eType == Token::tEndOfLine )
{
Bu::println( rOut, "Current scale: %1").
arg( lex.getScale() );
}
else if( t2.eType == Token::tString )
{
int32_t i = strtol( t2.sVal->getStr(), 0, 10 );
lex.setScale( i );
if( i < 0 )
{
Bu::println( rOut, "ERROR: You must provide a "
"positive integer or zero as the parameter "
"to scale.");
}
else
{
Bu::println( rOut, "Scale changed to: %1").
arg( lex.getScale() );
for( VarHash::iterator i = hVars.begin(); i; i++ )
(*i).setScale( lex.getScale() );
nZero = Number( lex.getScale(), lex.getRadix() );
}
}
else
{
Bu::println( rOut, "ERROR: You must provide a number "
"as the parameter to scale.");
}
}
else if( *t.sVal == "radix" )
{
Token t2 = lex.nextToken();
if( t2.eType == Token::tEndOfLine )
{
Bu::println( rOut, "Current radix: %1").
arg( lex.getRadix() );
}
else if( t2.eType == Token::tString )
{
int32_t i = strtol( t2.sVal->getStr(), 0, 10 );
if( i < 2 || i > 36 )
Bu::println( rOut, "ERROR: Radix must be between "
"2 and 36 inclusive");
else
{
lex.setRadix( i );
Bu::println( rOut, "Radix changed to: %1").
arg( lex.getRadix() );
hVars.clear();
nZero = Number( lex.getScale(), lex.getRadix() );
}
}
else
{
Bu::println( rOut, "You must provide a number as "
"the parameter to radix.");
}
}
else if( *t.sVal == "vars" )
{
Bu::println( rOut, "Declared variables:");
for( VarHash::iterator i = hVars.begin(); i; i++ )
{
Bu::println( rOut, " - %1 = %2").
arg( i.getKey() ).arg( *i );
}
Bu::println( rOut, "");
}
else if( *t.sVal == "help" || *t.sVal == "h" || *t.sVal == "?" )
{
Bu::println( rOut, Datafiles::getString("parserhelp.txt") );
}
else
{
Bu::println( rOut, "ERROR: Unknown command '%1'").
arg( *t.sVal );
}
lex.setMode( Lexer::modeNormal );
break;
case Token::tNumber:
case Token::tVariable:
tsTerminal.push( t );
break;
default:
if( tsNonTerminal.getSize() == 0 ||
getPriority( tsNonTerminal.peek().eType ) <
getPriority( t.eType ) )
{
DBS( PARSE,
Bu::println("Pushing non-terminal: %1").arg( t.eType )
);
tsNonTerminal.push( t );
}
else
{
DBS( PARSE,
Bu::println("Unwinding stack before pushing: %1")
.arg( t.eType )
);
unwind();
tsNonTerminal.push( t );
}
break;
}
}
}
Number Parser::getVariable( const Bu::String &sName )
{
return hVars.get( sName );
}
void Parser::setVariable( const Bu::String &sName, const Number &rValue )
{
hVars.insert( sName, rValue );
}
void Parser::unwind()
{
for(;;)
{
DBS_START( PARSE );
for( TokenStack::iterator i = tsTerminal.begin(); i; i++ )
{
if( (*i).eType == Token::tNumber )
Bu::print(" [%1]").arg( *(*i).nVal );
else
Bu::print(" [%1]").arg( *(*i).sVal );
}
Bu::println("");
for( TokenStack::iterator i = tsNonTerminal.begin(); i; i++ )
Bu::print(" <%1>").arg( (*i).eType );
Bu::println("");
DBS_END();
if( tsNonTerminal.isEmpty() )
return;
if( tsTerminal.getSize() < reqTokens( tsNonTerminal.peek().eType ) )
{
return;
}
Token t = tsNonTerminal.peekPop();
switch( t.eType )
{
case Token::tPlus:
{
Token b = tsTerminal.peekPop();
Token a = tsTerminal.peekPop();
tsTerminal.push(
Token( Token::tNumber,
new Number( deref(a) + deref(b) )
)
);
}
break;
case Token::tMinus:
{
Token b = tsTerminal.peekPop();
Token a = tsTerminal.peekPop();
tsTerminal.push(
Token( Token::tNumber,
new Number( deref(a) - deref(b) )
)
);
}
break;
case Token::tMultiply:
{
Token b = tsTerminal.peekPop();
Token a = tsTerminal.peekPop();
Number *pProduct = new Number( deref(a) * deref(b) );
pProduct->setScale( lex.getScale() );
tsTerminal.push(
Token( Token::tNumber,
pProduct
)
);
}
break;
case Token::tDivide:
{
Token b = tsTerminal.peekPop();
Token a = tsTerminal.peekPop();
tsTerminal.push(
Token( Token::tNumber,
new Number( deref(a) / deref(b) )
)
);
}
break;
case Token::tModulus:
{
Token b = tsTerminal.peekPop();
Token a = tsTerminal.peekPop();
tsTerminal.push(
Token( Token::tNumber,
new Number( deref(a) % deref(b) )
)
);
}
break;
case Token::tOpenParen:
tsNonTerminal.push( t );
return;
case Token::tCloseParen:
unwind();
if( tsNonTerminal.peek().eType == Token::tOpenParen )
{
tsNonTerminal.pop();
unwind();
}
else
{
throw Bu::ExceptionBase("Close paren found without open paren.");
}
break;
case Token::tEquals:
{
Token b = tsTerminal.peekPop();
Token a = tsTerminal.peekPop();
if( a.eType != Token::tVariable )
{
Bu::println("The left hand side of a = must be a variable.");
tsTerminal.clear();
tsNonTerminal.clear();
return;
}
hVars.insert( *a.sVal, deref( b ) );
tsTerminal.push(
Token( Token::tNumber,
new Number( deref( b ) )
)
);
}
break;
case Token::tNumber:
case Token::tVariable:
case Token::tCommand:
case Token::tString:
case Token::tEndOfLine:
case Token::tEndOfInput:
// These should never show up at all
break;
}
if( !tsNonTerminal.isEmpty() &&
getPriority( tsNonTerminal.peek().eType ) <
getPriority( t.eType ) )
return;
}
}
int Parser::reqTokens( Token::Type eType )
{
switch( eType )
{
case Token::tPlus:
case Token::tMinus:
case Token::tDivide:
case Token::tMultiply:
case Token::tModulus:
case Token::tEquals:
return 2;
case Token::tOpenParen:
return 0;
case Token::tCloseParen:
return 1;
default:
return 0;
}
}
int Parser::getPriority( Token::Type eType )
{
switch( eType )
{
case Token::tNumber:
case Token::tVariable:
case Token::tCommand:
return 0;
case Token::tPlus:
case Token::tMinus:
return 1;
case Token::tDivide:
case Token::tMultiply:
case Token::tModulus:
return 2;
case Token::tOpenParen:
case Token::tCloseParen:
return 3;
case Token::tEndOfLine:
case Token::tEndOfInput:
case Token::tEquals:
return -1;
default:
throw Bu::ExceptionBase("Invalid type in getPriority");
}
}
Number &Parser::deref( Token &t )
{
if( t.eType == Token::tNumber )
{
return *t.nVal;
}
else if( t.eType == Token::tVariable )
{
try
{
return hVars.get( *t.sVal );
}
catch(...)
{
return nZero;
}
}
else
{
throw Bu::ExceptionBase("Element was not a number or variable.");
}
}
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