update documentation and tests on prefix matching and clean up close match function.

README.md

@@ -914,6 +914,8 @@ option_groups. These are:
   is not allowed to have a single character short option starting with the same
   character as a single dash long form name; for example, `-s` and `-single` are
   not allowed in the same application.
+- `.allow_subcommand_prefix_matching()`:🚧  If this modifier is enabled, unambiguious prefix portions of a subcommand will match.
+  For example `upgrade_package`  would match on `upgrade_`,  `upg`, `u` as long as no other subcommand would also match.   It also disallows subcommand names that are full prefixes of another subcommand. 
 - `.fallthrough()`: Allow extra unmatched options and positionals to "fall
   through" and be matched on a parent option. Subcommands by default are allowed
   to "fall through" as in they will first attempt to match on the current

book/chapters/subcommands.md

@@ -105,6 +105,7 @@ at the point the subcommand is created:
 - Fallthrough
 - Group name
 - Max required subcommands
+- prefix_matching
 - validate positional arguments
 - validate optional arguments
 
@@ -156,6 +157,11 @@ ignored, even if they could match. Git is the traditional example for prefix
 commands; if you run git with an unknown subcommand, like "`git thing`", it then
 calls another command called "`git-thing`" with the remaining options intact.
 
+### prefix matching
+
+A modifier is available for subcommand matching,  `->allow_subcommand_prefix_matching()`.   if this is enabled unambiguious prefix portions of a subcommand will match.
+For Example `upgrade_package`  would match on `upgrade_`,  `upg`, `u` as long as no other subcommand would also match.   It also disallows subcommand names that are full prefixes of another subcommand. 
+
 ### Silent subcommands
 
 Subcommands can be modified by using the `silent` option. This will prevent the

examples/CMakeLists.txt

@@ -252,6 +252,19 @@ set_property(TEST retired_deprecated PROPERTY PASS_REGULAR_EXPRESSION "deprecate
 
 add_cli_exe(close_match close_match.cpp)
 
+add_test(NAME close_match_test COMMAND close_match i)
+add_test(NAME close_match_test2 COMMAND close_match upg)
+add_test(NAME close_match_test3 COMMAND close_match rem)
+add_test(NAME close_match_test4 COMMAND close_match upgrde)
+
+set_property(TEST close_match_test PROPERTY PASS_REGULAR_EXPRESSION "install")
+
+set_property(TEST close_match_test2 PROPERTY PASS_REGULAR_EXPRESSION "upgrade")
+
+set_property(TEST close_match_test3 PROPERTY PASS_REGULAR_EXPRESSION "remove")
+
+set_property(TEST close_match_test4 PROPERTY PASS_REGULAR_EXPRESSION "closest match is upgrade")
+
 #--------------------------------------------
 add_cli_exe(custom_parse custom_parse.cpp)
 add_test(NAME cp_test COMMAND custom_parse --dv 1.7)

examples/close_match.cpp

@@ -12,29 +12,33 @@
 #include <string>
 #include <utility>
 #include <vector>
+#include <numeric>
 
-// Levenshtein distance function code generated by chatgpt
-std::size_t levenshteinDistance(const std::string &s1, const std::string &s2) {
-    size_t len1 = s1.size(), len2 = s2.size();
-    std::vector<std::vector<std::size_t>> dp(len1 + 1, std::vector<std::size_t>(len2 + 1));
+// Levenshtein distance function code generated by chatgpt/copilot
+std::size_t levenshteinDistance(const std::string& s1, const std::string& s2) {
+    std::size_t len1 = s1.size(), len2 = s2.size();
+    if (len1 == 0) return len2;
+    if (len2 == 0) return len1;
 
-    for(size_t ii = 0; ii <= len1; ++ii)
-        dp[ii][0] = ii;
-    for(size_t jj = 0; jj <= len2; ++jj)
-        dp[0][jj] = jj;
+    std::vector<std::size_t> prev(len2 + 1), curr(len2 + 1);
+    std::iota(prev.begin(), prev.end(), 0);  // Fill prev with {0, 1, ..., len2}
 
-    for(size_t ii = 1; ii <= len1; ++ii) {
-        for(size_t jj = 1; jj <= len2; ++jj) {
+    for (std::size_t ii = 1; ii <= len1; ++ii) {
+        curr[0] = ii;
+        for (std::size_t jj = 1; jj <= len2; ++jj) {
+            // If characters match, no substitution cost; otherwise, cost is 1.
             std::size_t cost = (s1[ii - 1] == s2[jj - 1]) ? 0 : 1;
-            dp[ii][jj] = (std::min)({
-                dp[ii - 1][jj] + 1,        // deletion
-                dp[ii][jj - 1] + 1,        // insertion
-                dp[ii - 1][jj - 1] + cost  // substitution
-            });
-        }
-    }
 
-    return dp[len1][len2];
+            // Compute the minimum cost between:
+            // - Deleting a character from `s1` (prev[jj] + 1)
+            // - Inserting a character into `s1` (curr[jj - 1] + 1)
+            // - Substituting a character (prev[jj - 1] + cost)
+
+            curr[jj] = std::min({ prev[jj] + 1, curr[jj - 1] + 1, prev[jj - 1] + cost });
+        }
+        prev = std::exchange(curr, prev);  // Swap vectors efficiently
+    }
+    return prev[len2];
 }
 
 // Finds the closest string from a list (modified from chat gpt code)
@@ -53,30 +57,33 @@ std::pair<std::string, std::size_t> findClosestMatch(const std::string &input,
     return {closest, minDistance};
 }
 
-void addCloseMatchDetection(CLI::App *app, std::size_t minDistance = 3) {
+void addSubcommandCloseMatchDetection(CLI::App *app, std::size_t minDistance = 3) {
+    //if extras are not allowed then there will be no remaining
     app->allow_extras(true);
-
-    app->parse_complete_callback([&app, minDistance]() {
+    // generate a list of subcommand names
+    auto subs = app->get_subcommands(nullptr);
+    std::vector<std::string> list;
+    for(const auto *sub : subs) {
+        if(!sub->get_name().empty()) {
+            list.push_back(sub->get_name());
+        }
+        auto aliases = sub->get_aliases();
+        if(!aliases.empty()) {
+            list.insert(list.end(), aliases.begin(), aliases.end());
+        }
+    }
+    // add a callback that runs before a final callback and loops over the remaining arguments for subcommands
+    app->parse_complete_callback([&app, minDistance,list]() {
         auto extras = app->remaining();
         if(extras.empty()) {
             return;
         }
-        auto subs = app->get_subcommands(nullptr);
-        std::vector<std::string> list;
-        for(const auto *sub : subs) {
-            if(!sub->get_name().empty()) {
-                list.push_back(sub->get_name());
-            }
-            auto aliases = sub->get_aliases();
-            if(!aliases.empty()) {
-                list.insert(list.end(), aliases.begin(), aliases.end());
-            }
-        }
+        
         for(auto &extra : extras) {
             if(extra.front() != '-') {
                 auto closest = findClosestMatch(extra, list);
                 if(closest.second <= minDistance) {
-                    std::cout << "unmatched commands " << extra << ", closest match is " << closest.first << "\n";
+                    std::cout << "unmatched command \"" << extra << "\", closest match is " << closest.first << "\n";
                 }
             }
         }
@@ -86,7 +93,7 @@ void addCloseMatchDetection(CLI::App *app, std::size_t minDistance = 3) {
 /** This example demonstrates the use of close match detection to detect invalid commands that are close matches to
  * existing ones
  */
-int main(int argc, const char *argv[]) {
+int main(int argc, const char* argv[]) {
 
     int value{0};
     CLI::App app{"cose string App"};
@@ -98,7 +105,14 @@ int main(int argc, const char *argv[]) {
     app.add_subcommand("upgrade", "");
     app.add_subcommand("remove", "");
     app.add_subcommand("test", "");
-    addCloseMatchDetection(&app, 5);
+    //enable close matching for subcommands
+    addSubcommandCloseMatchDetection(&app, 5);
     CLI11_PARSE(app, argc, argv);
+
+    auto subs=app.get_subcommands();
+    for (const auto& sub : subs)
+    {
+        std::cout<<sub->get_name()<<"\n";
+    }
     return 0;
 }