1 files changed, 112 insertions, 0 deletions
diff --git a/libalee/parser.cpp b/libalee/parser.cpp
new file mode 100644
index 0000000..44b5cec
--- /dev/null
+++ b/libalee/parser.cpp
@@ -0,0 +1,112 @@
+/**
+ * Alee Forth: A portable and concise Forth implementation in modern C++.
+ * Copyright (C) 2023  Clyne Sullivan <clyne@bitgloo.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "corewords.hpp"
+#include "parser.hpp"
+
+#include <charconv>
+#include <cstring>
+
+int Parser::parse(State& state, const char *str)
+{
+    auto addr = Dictionary::Input;
+    state.dict.write(addr, 0);
+    state.dict.write(Dictionary::SourceLen, std::strlen(str));
+
+    addr += sizeof(Cell);
+    while (*str)
+        state.dict.writebyte(addr++, *str++);
+
+    while (addr < Dictionary::Input + Dictionary::InputCells)
+        state.dict.writebyte(addr++, '\0');
+
+    return parseSource(state);
+}
+
+int Parser::parseSource(State& state)
+{
+    auto word = state.dict.input();
+    while (word.size() > 0) {
+        if (auto ret = parseWord(state, word); ret)
+            return ret;
+
+        word = state.dict.input();
+    }
+
+    return 0;
+}
+
+int Parser::parseWord(State& state, Word word)
+{
+    int ins, imm;
+
+    ins = state.dict.find(word);
+
+    if (ins <= 0) {
+        ins = CoreWords::findi(state, word);
+
+        if (ins < 0)
+            return parseNumber(state, word);
+        else
+            imm = ins == CoreWords::Semicolon;
+    } else {
+        imm = state.dict.read(ins) & CoreWords::Immediate;
+        ins = state.dict.getexec(ins);
+    }
+
+    if (state.compiling() && !imm)
+        state.dict.add(ins);
+    else if (auto stat = state.execute(ins); stat != State::Error::none)
+        return static_cast<int>(stat);
+
+    return 0;
+}
+
+int Parser::parseNumber(State& state, Word word)
+{
+    char buf[MaxCellNumberChars + 1];
+    unsigned i;
+    for (i = 0; i < std::min(MaxCellNumberChars, word.size()); ++i)
+        buf[i] = state.dict.readbyte(word.start + i);
+    buf[i] = '\0';
+
+    auto base = state.dict.read(0);
+    DoubleCell dl;
+    auto [ptr, ec] = std::from_chars(buf, buf + i, dl, base);
+    Cell l = static_cast<Cell>(dl);
+
+    if (ec == std::errc() && ptr == buf + i) {
+        if (state.compiling()) {
+            auto ins = CoreWords::findi("_lit");
+
+            //if (l >= 0 && l < 0xFF) {
+            //    state.dict.add(ins | ((l + 1) << 8));
+            //} else {
+                state.dict.add(ins);
+                state.dict.add(l);
+            //}
+        } else {
+            state.push(l);
+        }
+
+        return 0;
+    } else {
+        return UnknownWord;
+    }
+}
+