From 5e00d651f172f43917f381edef95c001ed97c904 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Thu, 16 Jan 2020 09:14:15 +0100
Subject: Lex concept

---
 minicc.cpp | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/minicc.cpp b/minicc.cpp
index f0f4e4c..e9bc918 100644
--- a/minicc.cpp
+++ b/minicc.cpp
@@ -46,6 +46,8 @@ struct TreeNode {
 using Tree = std::map<index_t, TreeNode>;
 
 bool ValidTree(const Tree& tree) {
+ // Start symbol?
+ // All terminal symbols?
  return true; // TODO
 }
 
@@ -61,7 +63,7 @@ std::vector<std::string> Lex(std::string s, std::string Top, BNF bnf)
 
  for (size_t pos{0}; pos < s.size(); pos++) {
   char c{s[pos]};
-  if (Whitespace.find(c) != std::string::npos) {
+  if (Whitespace.find(c) != std::string::npos) { // found whitespace character
    if (candidates.empty()) { // skip
     if (!token.empty())
      throw std::runtime_error("Expected empty token, got "s + token);
@@ -69,6 +71,8 @@ std::vector<std::string> Lex(std::string s, std::string Top, BNF bnf)
     bool valid{false};
     for (const auto& ct : candidates) {
      if (ValidTree(ct)) {
+      if (valid)
+       throw std::runtime_error("Found ambigous token");
       result.push_back(token);
       token.clear();
       valid = true;
@@ -80,15 +84,19 @@ std::vector<std::string> Lex(std::string s, std::string Top, BNF bnf)
     candidates.clear();
    }
   } else { // no whitespace: try to add to tree
-   for (const auto& ct : candidates) {
-    if (!TryAdd(cti, c)) {
-     candidates.erase(i); // no candidate anymore
+   for (auto& ct : candidates) {
+    EraseList;
+    if (!Add(ct, c)) {
+     EraseList.add(ct); // no candidate anymore
     }
    }
-   if (candidates.empty()) { // no candidates anymore
-   } else {
+
+   if (candidates.size() - EraseList.size() > 0) { // Added to some candidates: Continue growing token
+    token.push_back(c);
+    candidates.erase(EraseList);
+   } else { // no candidates left: new tree
+    // TODO: same as above "check candidates"
    }
-   //token.push_back(c);
   }
  }
 
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