1 files changed, 92 insertions, 0 deletions
diff --git a/parser.cpp b/parser.cpp
new file mode 100644
index 0000000..f80721a
--- /dev/null
+++ b/parser.cpp
@@ -0,0 +1,92 @@
+#include "parser.hpp"
+
+#include <cctype>
+#include <iostream>
+
+std::string name;
+
+static bool isname(char ch) {
+    return !isspace(ch) && ch != ')';
+}
+
+static std::string_view extractName(std::string_view sv)
+{
+    name.clear();
+
+    while (!sv.empty()) {
+        const auto ch = sv.front();
+
+        if (isname(ch)) {
+            name += ch;
+            sv.remove_prefix(1);
+        } else {
+            break;
+        }
+    }
+
+    return sv;
+}
+
+std::pair<std::string_view, Token> nextToken(std::string_view sv)
+{
+    if (sv.empty())
+        return {sv, Token::none};
+
+    while (std::isspace(sv.front()))
+        sv.remove_prefix(1);
+
+    if (sv.empty())
+        return {sv, Token::none};
+
+    const auto ch = sv.front();
+    if (ch == ';') {
+        return {{}, Token::none};
+    } else if (ch == '(') {
+        return {sv.substr(1), Token::ThunkOpen};
+    } else if (ch == ')') {
+        return {sv.substr(1), Token::ThunkClose};
+    } else if (ch == '\'') {
+        return {extractName(sv.substr(1)), Token::Quote};
+    } else if (ch == '$') {
+        return {extractName(sv.substr(1)), Token::PopVar};
+    } else if (ch == '^') {
+        return {extractName(sv.substr(1)), Token::PushVar};
+    } else if (isdigit(ch) || (ch == '-' && sv.size() > 1 && isdigit(sv[1]))) {
+        return {extractName(sv), Token::Number};
+    } else if (isname(ch)) {
+        return {extractName(sv), Token::Var};
+    }
+
+    return {sv, Token::none};
+}
+
+void printToken(Token tok)
+{
+    switch (tok) {
+    case Token::ThunkOpen:
+        std::cout << "ThunkOpen ";
+        break;
+    case Token::ThunkClose:
+        std::cout << "ThunkClose ";
+        break;
+    case Token::Quote:
+        std::cout << "Quote ";
+        break;
+    case Token::PopVar:
+        std::cout << "PopVar ";
+        break;
+    case Token::PushVar:
+        std::cout << "PushVar ";
+        break;
+    case Token::Var:
+        std::cout << "Var ";
+        break;
+    case Token::Number:
+        std::cout << "Number ";
+        break;
+    case Token::none:
+        //std::cout << "none ";
+        break;
+    }
+}
+