1 files changed, 124 insertions, 0 deletions
diff --git a/src/parse/tokenstream.cpp b/src/parse/tokenstream.cpp
new file mode 100644
index 00000000..5d9919f6
--- /dev/null
+++ b/src/parse/tokenstream.cpp
@@ -0,0 +1,124 @@
+/*
+ * MRustC - Rust Compiler
+ * - By John Hodge (Mutabah/thePowersGang)
+ *
+ * parse/tokenstream.cpp
+ * - TokenStream - Parser token source interface
+ */
+#include "tokenstream.hpp"
+#include <common.hpp>
+#include "parseerror.hpp"
+
+const bool DEBUG_PRINT_TOKENS = false;
+//const bool DEBUG_PRINT_TOKENS = true;
+//#define DEBUG_PRINT_TOKENS  debug_enabled("Lexer Tokens")
+
+TokenStream::TokenStream():
+    m_cache_valid(false)
+{
+}
+TokenStream::~TokenStream()
+{
+}
+
+Token TokenStream::innerGetToken()
+{
+    Token ret = this->realGetToken();
+    if( ret.get_pos().filename == "" )
+        ret.set_pos( this->getPosition() );
+    //DEBUG("ret.get_pos() = " << ret.get_pos());
+    return ret;
+}
+Token TokenStream::getToken()
+{
+    if( m_cache_valid )
+    {
+        m_cache_valid = false;
+        return mv$(m_cache);
+    }
+    else if( m_lookahead.size() )
+    {
+        Token ret = mv$( m_lookahead.front() );
+        m_lookahead.erase(m_lookahead.begin());
+        if( DEBUG_PRINT_TOKENS ) {
+            ::std::cout << "getToken[" << typeid(*this).name() << "] - " << ret.get_pos() << "-" << ret << ::std::endl;
+        }
+        return ret;
+    }
+    else
+    {
+        Token ret = this->innerGetToken();
+        if( DEBUG_PRINT_TOKENS ) {
+            ::std::cout << "getToken[" << typeid(*this).name() << "] - " << ret.get_pos() << "-" << ret << ::std::endl;
+        }
+        return ret;
+    }
+}
+void TokenStream::putback(Token tok)
+{
+    if( m_cache_valid )
+    {
+        DEBUG("" << getPosition() << " - Double putback: " << tok << " but " << m_cache);
+        throw ParseError::BugCheck("Double putback");
+    }
+    else
+    {
+        m_cache_valid = true;
+        m_cache = mv$(tok);
+    }
+}
+
+eTokenType TokenStream::lookahead(unsigned int i)
+{
+    const unsigned int MAX_LOOKAHEAD = 3;
+    
+    if( m_cache_valid )
+    {
+        if( i == 0 )
+            return m_cache.type();
+        i --;
+    }
+    
+    if( i >= MAX_LOOKAHEAD )
+        throw ParseError::BugCheck("Excessive lookahead");
+    
+    while( i >= m_lookahead.size() )
+    {
+        DEBUG("lookahead - read #" << m_lookahead.size());
+        m_lookahead.push_back( this->innerGetToken() );
+    }
+    
+    DEBUG("lookahead(" << i << ") = " << m_lookahead[i]);
+    return m_lookahead[i].type();
+}
+
+ProtoSpan TokenStream::start_span() const
+{
+    auto p = this->getPosition();
+    return ProtoSpan {
+        .filename = p.filename,
+        .start_line = p.line,
+        .start_ofs = p.ofs,
+        };
+}
+Span TokenStream::end_span(ProtoSpan ps) const
+{
+    auto p = this->getPosition();
+    return Span(
+        ps.filename,
+        ps.start_line, ps.start_ofs,
+        p.line, p.ofs
+        );
+}
+Ident TokenStream::get_ident(Token tok) const
+{
+    if(tok.type() == TOK_IDENT) {
+        return Ident(getHygiene(), tok.str());
+    }
+    else if( tok.type() == TOK_INTERPOLATED_IDENT ) {
+        TODO(getPosition(), "");
+    }
+    else {
+        throw ParseError::Unexpected(*this, tok);
+    }
+}