LICENSE, copyright, and formatting

.gitignore

@@ -1,2 +1 @@
 build
-.vscode

.vscode/settings.json

@@ -0,0 +1,4 @@
+{
+    "C_Cpp.clang_format_fallbackStyle": "Google",
+    "C_Cpp.clang_format_style": "{ColumnLimit: 100}"
+}

CMakeLists.txt

@@ -1,3 +1,5 @@
+# copyright Carl Pearson, 2022
+
 # 3.0: version
 cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
 

LICENSE

@@ -0,0 +1,202 @@
+
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+
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README.md

@@ -6,7 +6,7 @@ Simple single-file header-only CLI option parsing for C++ that does not require
 
 ## Getting Started
 
-Download the latest [`argparse.hpp`](https://raw.githubusercontent.com/cwpearson/argparse/latest/include/argparse/argparse.hpp) and include it in your project.
+Download the latest [`argparse.hpp`](https://raw.githubusercontent.com/cwpearson/argparse/master/include/argparse/argparse.hpp) and include it in your project.
 
 ## Example
 
@@ -16,19 +16,18 @@ Download the latest [`argparse.hpp`](https://raw.githubusercontent.com/cwpearson
 int main(int argc, char **argv) {
 
   // A parser object
-  Parser p;
+  argparse::Parser p;
 
   // Program data corresponding to flags, options, and positional arguments
   bool verbose = false;
   std::string toPrint;
   std::string maybePrint;
-  int repeats = 1;
+  int repeats = 2;
 
-  // Inform the parser of the program data. It will do type-specific conversion
+  // Inform the parser of the program data. It will do type-specific conversionfrom string.
-  // from string.
 
   // An option invoked with `--repeat N`
-  p.add_option(repeats, "--repeat");
+  p.add_option(repeats, "--repeat")->help("how many times to repeat first argument");
   // A flag invoked with `--verbose` or `-v`
   p.add_flag(verbose, "--verbose", "-v");
   // a required positional argument (position 1)
@@ -42,6 +41,12 @@ int main(int argc, char **argv) {
     exit(EXIT_FAILURE);
   }
 
+  // If help was requested, print it
+  if (p.need_help()) {
+    std::cerr << p.help();
+    return 0;
+  }
+
   // Execute the program logic
   if (verbose) {
     std::cerr << "about to print '" << toPrint << "' " << repeats << " times";
@@ -65,24 +70,29 @@ int main(int argc, char **argv) {
 
 ## Adding Options
 
-Options may be `int`, `size_t`, `float`, `double`, or `std::string` and currently support long strings.
+Options may be `int32_t`, `int64_t`, `size_t`, `float`, `double`, or `std::string`.
-They are invoked like `--long-opt value` (not `--long-opt=value`).
+They are invoked like `--long-opt value` (not `--long-opt=value`) or `-s value`, if provided.
+If they are not present, the value is not modified.
 
 ```c++
-Parser p;
+int var1 = 3; // a default value for var1
-p.add_option(var1, "--long-opt")
+argparse::Parser p;
+p.add_option(var1, "--long-opt");
+p.add_option(var2, "--long-opt, -s");
+p.add_option(var3, "--long-opt, -s")->help("a demo option");
 ```
 
 ## Adding Flags
 
 Flags are always `bool`s, and currently support long or short strings.
 The boolean variable is ALWAYS set to `true` if the flag is found.
-They are invoked like `--long-flag` (not `--long-flag=true` or `--long-flag true`).
+They are invoked like `--long-flag` (not `--long-flag=true` or `--long-flag true`) or `-s`, if provided.
 
 ```c++
-Parser p;
+argparse::Parser p;
 p.add_option(flag1, "--long-flag")
-p.add_option(flag2, "--antother-flag", "-s");
+p.add_option(flag2, "--another-flag", "-s");
+p.add_option(flag3, "--another-flag", "-s")->help("a demo flag");
 ```
 
 ## Positional Arguments
@@ -93,7 +103,7 @@ Use `required()` to require them.
 `add_positional()` returns a `PosnlBase *` that may be queried with `found()` to see if an optional positional argument was found.
 
 ```c++
-Parser p;
+argparse::Parser p;
 p.add_positional(var1)->required();
 auto something = p.add_positional(var2);
 if (something->found()) {
@@ -101,26 +111,61 @@ if (something->found()) {
 }
 ```
 
-## Parsing
+Anything after `--` is considered a positional argument, unless `--` follows an option.
+Here, the first `--` is the value for `--option` and will be in `s1`.
+The second `--` marks the beginning of positional arguments. and the string `aa` will be in `s2`.
 
 ```c++
-Parser p;
+argparse::Parser p;
+std::string s1, s2;
+p.add_option(s1, "--option");
+p.add_positional(s2);
+std::cerr << s1;
+std::cerr << s2;
+```
+
+```bash
+$ ./myexe --option -- -- aa
+--aa
+```
+
+## Parsing
+```c++
+argparse::Parser p;
 // set up flags, arguments, and options
 p.parse(argc, argv);
 ```
 
 `parse()` returns something falsy if there is an error.
-
 Parsing modifies `argc` and `argv` to remove consumed options by default.
 To disable, call `p->no_consume()`.
-
 Parsing will silently skip unrecognized arguments.
 To error instead, call `p->no_unrecognized()`.
 
+`Parser` provides a constructor that takes a string description.
+This description will be added to the usage string.
+```c++
+argparse::Parser p("a demo argparse CLI app");
+// set up flags, arguments, and options
+p.parse(argc, argv);
+```
+
+## Useage Strings
+A `--help` and `-h` flag are automatically added.
+`parser::need_help()` returns true if either of those flags are provided.
+`parser::help()` returns a string that contains the help output.
+
+```c++
+argparse::Parser p;
+if (p.need_help()) {
+  std::cout << p.help();
+}
+```
+
 ## Features
 
 - [x] Does not require `std::regex`
-- [x] allow (default) / disallow (`Parser::no_unrecognize()`) unrecognized options and flags
+- [x] allow (default) / disallow (`Parser::no_unrecognized()`) unrecognized options and flags
 - [x] optional/required (`PosnlBase::required()`) positional arguments
 - [x] flags with `-s`, `--long-flag` formats
 - [x] options with `--long-opt val` format
@@ -128,16 +173,24 @@ To error instead, call `p->no_unrecognized()`.
 - [x] `--` to stop parsing options and flags
 - [x] modify `argc`/`argv` (disable with `Parser::no_consume()`)
 - Option/Positional Argument Types
-  - [x] `int`
+  - [x] `int32_t`
+  - [x] `int64_t`
   - [x] `size_t`
   - [x] `float`
   - [x] `double`
   - [x] `std::string`
+- [x] Support short option strings
+- [x] Help string output
 
 ## Roadmap
 
-- [ ] Reject duplicate flags / options at run time
+- [ ] Runtime error if duplicate flags or options are defined
-- [ ] Support short option strings
+- [ ] support `--long-option=value`
-- [ ] Help string output
+- [ ] allow the last positional argument to fill an `std::vector`
-- [ ] support --long-option=value
+- [ ] improve help formatting
-- [ ] have the last positional argument fill a vector with remaining
+
+## License and Copyright
+
+Copyright Carl Pearson 2022
+
+Licensed under Apache 2.0 (see LICENSE for details).

examples/CMakeLists.txt

@@ -1,3 +1,5 @@
+# copyright Carl Pearson, 2022
+
 macro(add_args tgt)
 target_compile_options(
   ${tgt}

examples/example1.cpp

@@ -1,21 +1,22 @@
+// copyright Carl Pearson, 2022
+
 #include "argparse/argparse.hpp"
 
 int main(int argc, char **argv) {
 
   // A parser object
-  Parser p;
+  argparse::Parser p;
 
   // Program data corresponding to flags, options, and positional arguments
   bool verbose = false;
   std::string toPrint;
   std::string maybePrint;
-  int repeats = 1;
+  int repeats = 2;
 
-  // Inform the parser of the program data. It will do type-specific conversion
+  // Inform the parser of the program data. It will do type-specific conversionfrom string.
-  // from string.
 
   // An option invoked with `--repeat N`
-  p.add_option(repeats, "--repeat");
+  p.add_option(repeats, "--repeat")->help("how many times to repeat first argument");
   // A flag invoked with `--verbose` or `-v`
   p.add_flag(verbose, "--verbose", "-v");
   // a required positional argument (position 1)
@@ -29,6 +30,12 @@ int main(int argc, char **argv) {
     exit(EXIT_FAILURE);
   }
 
+  // If help was requested, print it
+  if (p.need_help()) {
+    std::cerr << p.help();
+    return 0;
+  }
+
   // Execute the program logic
   if (verbose) {
     std::cerr << "about to print '" << toPrint << "' " << repeats << " times";

include/argparse/argparse.hpp

@@ -1,31 +1,78 @@
+// copyright Carl Pearson, 2022
+
 #pragma once
 
-#include <string>
-#include <vector>
 #include <iostream>
 #include <sstream>
+#include <string>
+#include <vector>
 
+namespace argparse {
 
+namespace detail {
+template <typename T> const char *type_str();
+template <> const char *type_str<int32_t>() { return "INT32"; }
+template <> const char *type_str<int64_t>() { return "INT64"; }
+template <> const char *type_str<std::string>() { return "STR"; }
+template <> const char *type_str<float>() { return "F32"; }
+template <> const char *type_str<double>() { return "F64"; }
+template <> const char *type_str<size_t>() { return "SIZE_T"; }
+} // namespace detail
 
+class Parser;
 
+/* Interface for an object representing a command-line option
+ */
 class OptionBase {
+  friend class Parser;
+
 public:
-  virtual void set_val(const std::string &valStr) = 0;
+  /* return the short and long options
+   */
+  virtual const std::string &short_str() = 0;
   virtual const std::string &long_str() = 0;
+
+  /* return the help string
+   */
+  virtual const std::string &help_str() = 0;
+
+  /* set help string
+   */
+  virtual void help(const std::string &s) = 0;
+
+private:
+  /* a string representing the type of the option (INT, STR, FLOAT)
+   */
+  virtual const char *type_str() = 0;
+
+  /* set the value provided to this option
+   */
+  virtual void set_val(const std::string &valStr) = 0;
 };
 
 template <typename T> class Option : public OptionBase {
+  std::string short_;
   std::string long_;
+  std::string help_;
   T *val_;
 
 public:
-  Option(T &val, const std::string &l) : long_(l), val_(&val) {}
+  Option(T &val, const std::string &l, const std::string &s = "")
-  void set_val(const std::string &val) override { set_val((T *)nullptr, val); }
+      : long_(l), short_(s), val_(&val) {}
-  const std::string &long_str() override {
+  const std::string &long_str() override { return long_; }
-      return long_;
+  const std::string &short_str() override { return short_; }
-  }
+  const std::string &help_str() override { return help_; }
+
+  void help(const std::string &s) { help_ = s; }
 
 private:
+  /* uses a T* = nullpointer to disambiguate the call
+   */
+  const char *type_str() override { return detail::type_str<T>(); }
+  void set_val(const std::string &val) override { set_val((T *)nullptr, val); }
+
+  /* how to parse supported types
+   */
   void set_val(size_t *, const std::string &val) { // convert to size_t
     *val_ = std::stoull(val);
   }
@@ -35,7 +82,10 @@ private:
   void set_val(float *, const std::string &val) { // convert to float
     *val_ = std::stof(val);
   }
-  void set_val(int *, const std::string &val) { // convert to int
+  void set_val(int32_t *, const std::string &val) { // convert to int32_t
+    *val_ = std::stoi(val);
+  }
+  void set_val(int64_t *, const std::string &val) { // convert to int64_t
     *val_ = std::stoi(val);
   }
   void set_val(std::string *, const std::string &val) { // convert to string
@@ -43,6 +93,8 @@ private:
   }
 };
 
+/* Represents a command-line flag
+ */
 class Flag {
   std::string long_;
   std::string short_;
@@ -57,21 +109,22 @@ public:
 
   void set() const noexcept { *val_ = true; }
 
-  void help(const std::string &s) {
+  void help(const std::string &s) { help_ = s; }
-    help_ = s;
-  }
 
-  const std::string &help_str() const noexcept {
+  const std::string &help_str() const noexcept { return help_; }
-    return help_;
-  }
 };
 
 class PosnlBase {
+  friend class Parser;
+
 public:
   virtual bool is_required() = 0;
   virtual PosnlBase *required() = 0;
   virtual void set_val(const std::string &val) = 0;
   virtual bool found() = 0;
+
+private:
+  virtual const char *type_str() = 0;
 };
 
 template <typename T> class Positional : public PosnlBase {
@@ -99,9 +152,9 @@ public:
   bool found() override { return found_; }
 
 private:
-  // https://stackoverflow.com/questions/5512910/explicit-specialization-of-template-class-member-function
+  const char *type_str() override { return detail::type_str<T>(); }
-  template <typename C>
+
-  void get_as(C *, const std::string &val) { // to be overridden
+  template <typename C> void get_as(C *, const std::string &val) { // to be overridden
   }
   void set_val(size_t *, const std::string &val) { // convert to size_t
     *val_ = std::stoull(val);
@@ -112,7 +165,10 @@ private:
   void set_val(float *, const std::string &val) { // convert to float
     *val_ = std::stof(val);
   }
-  void set_val(int *, const std::string &val) { // convert to int
+  void set_val(int32_t *, const std::string &val) { // convert to int32_t
+    *val_ = std::stoi(val);
+  }
+  void set_val(int64_t *, const std::string &val) { // convert to int64_t
     *val_ = std::stoi(val);
   }
   void set_val(std::string *, const std::string &val) { // convert to string
@@ -131,6 +187,8 @@ class Parser {
   std::vector<Flag> flags_;
   std::vector<PosnlBase *> posnls_;
 
+  std::string argv0_; // will hold the name of the most recent parse(...)
+
   static bool starts_with(const std::string &s, const std::string &prefix) {
     if (s.rfind(prefix, 0) == 0) {
       return true;
@@ -140,8 +198,10 @@ class Parser {
 
   OptionBase *match_opt(const char *arg) const {
     std::string sarg(arg);
+
+    // match options back-to-front to prefer later duplicates
     for (int64_t i = int64_t(opts_.size()) - 1; i >= 0; --i) {
-      if (opts_[i]->long_str() == sarg) {
+      if (opts_[i]->long_str() == sarg || opts_[i]->short_str() == sarg) {
         return opts_[i];
       }
     }
@@ -150,6 +210,8 @@ class Parser {
 
   Flag *match_flag(const char *arg) {
     std::string sarg(arg);
+
+    // match flags back-to-front to prefer later duplicates
     for (int64_t i = int64_t(flags_.size()) - 1; i >= 0; --i) {
       if (flags_[i].long_str() == sarg || flags_[i].short_str() == sarg) {
         return &flags_[i];
@@ -159,11 +221,13 @@ class Parser {
   }
 
 public:
-
+  Parser()
-  Parser() : noUnrecognized_(false), help_(false), consume_(true) {
+      : description_("an argparse-powered program"), noUnrecognized_(false), help_(false),
+        consume_(true) {
     add_flag(help_, "--help", "-h")->help("Print help message");
   }
-  Parser(const std::string &description) : description_(description), noUnrecognized_(false), help_(false), consume_(true) {
+  Parser(const std::string &description)
+      : description_(description), noUnrecognized_(false), help_(false), consume_(true) {
     add_flag(help_, "--help", "-h")->help("Print help message");
   }
 
@@ -172,16 +236,22 @@ public:
     std::vector<char *> newArgv;
     if (argc > 0) {
       newArgv.push_back(argv[0]);
+
+      if (argv[0]) {
+        argv0_ = argv[0];
+      } else {
+        argv0_ = "";
+      }
     }
 
     size_t pi = 0;        // positional argument position
     bool optsOkay = true; // okay to interpret as opt/flag
     for (int i = 1; i < argc; ++i) {
 
-
       // try interpreting as a flag or option if it looks like one
       if (optsOkay && starts_with(argv[i], "-")) {
         // '--' indicates only positional arguments follow
+        // the second '--' should be interpreted as a positional argument
         if (argv[i] == std::string("--")) {
           optsOkay = false;
           continue;
@@ -228,12 +298,13 @@ public:
       }
     }
 
-
     return true;
   };
 
-  template <typename T> void add_option(T &val, const std::string &l) {
+  template <typename T>
-    opts_.push_back(new Option<T>(val, l));
+  OptionBase *add_option(T &val, const std::string &l, const std::string &s = "") {
+    opts_.push_back(new Option<T>(val, l, s));
+    return opts_.back();
   }
 
   Flag *add_flag(bool &val, const std::string &l, const std::string &s = "") {
@@ -249,10 +320,26 @@ public:
   std::string help() const {
     std::stringstream ss;
 
+    ss << "Usage: " << argv0_ << " [OPTION]...";
+
+    for (auto &p : posnls_) {
+      ss << " ";
+      ss << (p->is_required() ? "" : "[");
+      ss << p->type_str();
+      ss << (p->is_required() ? "" : "]");
+    }
+    ss << "\n";
+
     ss << description_ << "\n";
 
     for (auto &o : opts_) {
-      ss << o->long_str() << "\n";
+      ss << "  ";
+      if (!o->short_str().empty()) {
+        ss << o->short_str() << ", ";
+      }
+      ss << o->long_str() << "\t" << o->type_str();
+      ss << "\t\t" << o->help_str();
+      ss << "\n";
     }
 
     for (auto &f : flags_) {
@@ -266,17 +353,13 @@ public:
 
   /*! \brief error on unrecognized flags and options
    */
-  void no_unrecognized() {
+  void no_unrecognized() { noUnrecognized_ = true; }
-    noUnrecognized_ = true;
-  }
 
   /*! \brief don't modify argc/argv
    */
-  void no_consume() {
+  void no_consume() { consume_ = false; }
-    consume_ = false;
-  }
 
-  bool need_help() const noexcept {
+  bool need_help() const noexcept { return help_; }
-    return help_;
-  }
 };
+
+} // namespace argparse

test/CMakeLists.txt

@@ -1,3 +1,5 @@
+# copyright Carl Pearson, 2022
+
 macro(add_args tgt)
 target_compile_options(
   ${tgt}

test/test_argparse.cpp

@@ -1,3 +1,5 @@
+// copyright Carl Pearson, 2022
+
 #include "catch2/catch.hpp"
 
 #include <iostream>
@@ -6,22 +8,36 @@
 
 TEST_CASE("argparse") {
 
+  SECTION("no args") {
+    char **argv = nullptr;
+    int argc = 0;
+    argparse::Parser p;
+    REQUIRE(p.parse(argc, argv));
+  }
+
+  SECTION("null argv[0]") {
+    char *argv[] = {nullptr};
+    int argc = sizeof(argv) / sizeof(argv[0]);
+    argparse::Parser p;
+    REQUIRE(p.parse(argc, argv));
+  }
+
   SECTION("types") {
     char *argv[] = {
         "some-exe",   "--campi", "--f", "10", "1.7", "1.8",
         "--", // stop looking for options
-        "--a string",
+        "--a string", "-6",
-        "-6",
     };
     int argc = sizeof(argv) / sizeof(argv[0]);
 
-    Parser p;
+    argparse::Parser p;
 
     bool campi = false;
     size_t x;
     double d;
     float f;
     int i;
+    int64_t i64;
     std::string s;
     p.add_flag(campi, "--campi");
     p.add_positional(x);
@@ -29,6 +45,7 @@ TEST_CASE("argparse") {
     p.add_positional(f);
     p.add_positional(s);
     p.add_positional(i);
+    p.add_positional(i64);
     REQUIRE(p.parse(argc, argv));
 
     REQUIRE(campi == true);
@@ -42,21 +59,13 @@ TEST_CASE("argparse") {
     REQUIRE(argc == 2); // does not use --f or some-exe
   }
 
-  SECTION("no args") {
-    char *argv[] = {nullptr};
-    int argc = sizeof(argv) / sizeof(argv[0]);
-    Parser p;
-    REQUIRE(p.parse(argc, argv));
-  }
-
-
   SECTION("description") {
     char *argv[] = {
         "some-exe",
     };
     int argc = sizeof(argv) / sizeof(argv[0]);
 
-    Parser p("a test program");
+    argparse::Parser p("a test program");
     REQUIRE(p.parse(argc, argv));
   }
 
@@ -64,7 +73,7 @@ TEST_CASE("argparse") {
     char *argv[] = {"some-exe"};
     int argc = sizeof(argv) / sizeof(argv[0]);
 
-    Parser p;
+    argparse::Parser p;
     p.no_unrecognized();
     REQUIRE(p.parse(argc, argv));
   }
@@ -73,7 +82,7 @@ TEST_CASE("argparse") {
     char *argv[] = {"some-exe", "-f"};
     int argc = sizeof(argv) / sizeof(argv[0]);
 
-    Parser p;
+    argparse::Parser p;
     p.no_unrecognized();
     REQUIRE(false == p.parse(argc, argv));
   }
@@ -85,7 +94,7 @@ TEST_CASE("argparse") {
     std::string a;
     std::string b;
 
-    Parser p;
+    argparse::Parser p;
     p.add_positional(a)->required();
     p.add_positional(b)->required();
     REQUIRE(false == p.parse(argc, argv));
@@ -95,24 +104,16 @@ TEST_CASE("argparse") {
     char *argv[] = {"some-exe", "-h"};
     int argc = sizeof(argv) / sizeof(argv[0]);
 
-    std::string a;
+    argparse::Parser p;
-    std::string b;
-
-    Parser p;
     REQUIRE(true == p.parse(argc, argv));
     REQUIRE(p.need_help());
-
-    std::cerr << p.help() << "\n";
   }
 
   SECTION("--help") {
     char *argv[] = {"some-exe", "--help"};
     int argc = sizeof(argv) / sizeof(argv[0]);
 
-    std::string a;
+    argparse::Parser p;
-    std::string b;
-
-    Parser p;
     REQUIRE(true == p.parse(argc, argv));
     REQUIRE(p.need_help());
   }
@@ -121,12 +122,45 @@ TEST_CASE("argparse") {
     char *argv[] = {"some-exe", "--help", "--"};
     int argc = sizeof(argv) / sizeof(argv[0]);
 
-    std::string a;
+    argparse::Parser p;
-    std::string b;
-
-    Parser p;
     REQUIRE(true == p.parse(argc, argv));
     REQUIRE(p.need_help());
   }
 
+  SECTION("double --") {
+    char *argv[] = {"some-exe", "--flag", "--", "--", "aa"};
+    int argc = sizeof(argv) / sizeof(argv[0]);
+
+    std::string a, b;
+    bool flag = false;
+
+    argparse::Parser p;
+    p.add_flag(flag, "--flag");
+    p.add_positional(a);
+    p.add_positional(b);
+
+    REQUIRE(true == p.parse(argc, argv));
+    REQUIRE(!p.need_help());
+
+    REQUIRE(a == "--");
+    REQUIRE(b == "aa");
+    REQUIRE(flag == true);
+  }
+
+  SECTION("-- in option") {
+    char *argv[] = {"some-exe", "--option", "--", "--", "aa"};
+    int argc = sizeof(argv) / sizeof(argv[0]);
+
+    std::string a, option;
+
+    argparse::Parser p;
+    p.add_option(option, "--option");
+    p.add_positional(a);
+
+    REQUIRE(true == p.parse(argc, argv));
+    REQUIRE(!p.need_help());
+
+    REQUIRE(a == "aa");
+    REQUIRE(option == "--");
+  }
 }

test/test_main.cpp

@@ -1,2 +1,4 @@
+// copyright Carl Pearson, 2022
+
 #define CATCH_CONFIG_MAIN // This tells Catch to provide a main() - only do this in one cpp file
 #include "catch2/catch.hpp"