feat: add help option printing, add descriptionv2.2

2 files changed, 40 insertions, 11 deletions

diff --git a/examples/basic_example.c b/examples/basic_example.c
index 2f77b6c..43413f4 100644
--- a/examples/basic_example.c
+++ b/examples/basic_example.c
@@ -9,24 +9,24 @@ int main(int argc, char** argv) {
     const char* testfile;
 
     ls_args_init(&args);
+    args.help_description = "An example program to show how arguments work. "
+                            "Provide an input file and optionally an output "
+                            "file and test file and see what happens!";
     ls_args_bool(&args, &help, "h", "help", "Prints help", 0);
     ls_args_string(&args, &outfile, "o", "out",
         "Specify the outfile, default 'out.txt'", 0);
-    ls_args_pos_string(&args, &infile, "Input file", LS_ARGS_REQUIRED);
-    ls_args_pos_string(&args, &testfile, "Test file", 0);
+    ls_args_pos_string(&args, &infile, "input file", LS_ARGS_REQUIRED);
+    ls_args_pos_string(&args, &testfile, "test file", 0);
     if (!ls_args_parse(&args, argc, argv)) {
-        printf("Error: %s\n", args.last_error);
-        puts(ls_args_help(&args));
+        if (help) {
+            puts(ls_args_help(&args));
+        } else {
+            printf("Error: %s\n", args.last_error);
+        }
         ls_args_free(&args);
         return 1;
     }
 
-    if (help) {
-        puts(ls_args_help(&args));
-        ls_args_free(&args);
-        return 0;
-    }
-
     printf("Got input file: %s\n", infile);
     printf("Got output file: %s\n", outfile);
     printf("Got test file: %s\n", testfile);
diff --git a/ls_args.h b/ls_args.h
index b66c462..de87a9b 100644
--- a/ls_args.h
+++ b/ls_args.h
@@ -1,7 +1,7 @@
 /* Lion's Standard (LS) ANSI C commandline argument parser with included help
  * renderer.
  *
- * Version: 2.1
+ * Version: 2.2
  * Website: https://libls.org
  * Repo: https://github.com/libls/args
  * SPDX-License-Identifier: MIT
@@ -136,6 +136,9 @@ typedef struct ls_args {
      * if you want to, for whatever reason. */
     const char* program_name;
 
+    /* description rendered under the "usage" line in ls_args_help */
+    const char* help_description;
+
     /* some bookkeeping -- these are used to free dynamically allocated memory
      * for help or errors cleanly on `ls_args_free`. */
     void* _allocated_error;
@@ -700,6 +703,32 @@ char* ls_args_help(ls_args* a) {
                     goto alloc_fail;
             }
         }
+        if (a->help_description) {
+            if (!_lsa_buffer_append_cstr(&help, "\n\n"))
+                goto alloc_fail;
+            if (!_lsa_buffer_append_cstr(&help, a->help_description))
+                goto alloc_fail;
+        }
+        if (!_lsa_buffer_append_cstr(&help, "\n\nOptions:"))
+            goto alloc_fail;
+        for (i = 0; i < a->args_len; ++i) {
+            if (!a->args[i].is_pos) {
+                if (!_lsa_buffer_append_cstr(&help, "\n  -"))
+                    goto alloc_fail;
+                if (!_lsa_buffer_append_cstr(
+                        &help, a->args[i].match.name.short_opt))
+                    goto alloc_fail;
+                if (!_lsa_buffer_append_cstr(&help, " \t--"))
+                    goto alloc_fail;
+                if (!_lsa_buffer_append_cstr(
+                        &help, a->args[i].match.name.long_opt))
+                    goto alloc_fail;
+                if (!_lsa_buffer_append_cstr(&help, " \t\t"))
+                    goto alloc_fail;
+                if (!_lsa_buffer_append_cstr(&help, a->args[i].help))
+                    goto alloc_fail;
+            }
+        }
     }
 
     a->_allocated_help = help.data;