infer short flags

src/hwylterm/hwylcli.nim

@@ -191,11 +191,12 @@ type
     ShowHelp,     ## If cmdline empty show help
     NoNormalize,  ## Don't normalize flags and commands
     NoPositional, ## Raise error if any remaing positional arguments DEPRECATED
-    HideDefault   ## Don't show default values
+    HideDefault,  ## Don't show default values
-    # ExactArgs,    ## Raise error if missing positional argument
+    InferShort    ## Autodefine short flags
 
   CliFlagSetting* = enum
-    HideDefault   ## Don't show default values
+    HideDefault,   ## Don't show default values
+    NoShort        ## Counter option to Parent's InferShort
 
   BuiltinFlag = object
     name*: string
@@ -269,6 +270,9 @@ template `<<<`(n: NimNode) {.used.} =
   ## for debugging macros
   <<< treeRepr n
 
+template `<<<`(n: untyped) {.used.} =
+  debugEcho n, "|||", instantiationInfo().line
+
 func `<<<`(f: CliFlag) {.used.}=
   var s: string
   let fields = [
@@ -398,6 +402,19 @@ func parseCliFlag(n: NimNode): CliFlag =
   if result.ident == nil:
     result.ident = result.name.ident
 
+func inferShortFlags(cfg: var CliCfg) =
+  ## supplement existing short flags based on initial characters of long flags
+  let taken = cfg.flags.mapIt(it.short).toHashSet() - toHashSet(['\x00'])
+  var candidates = cfg.flags.mapIt(it.long[0]).toHashSet() - taken
+  for f in cfg.flags.mitems:
+
+    if f.short != '\x00' or NoShort in f.settings: continue
+    let c = f.long[0]
+    if c in candidates:
+      f.short = c
+      candidates.excl c
+
+
 func postParse(cfg: var CliCfg) =
   if cfg.name == "":
     error "missing required option: name"
@@ -417,6 +434,9 @@ func postParse(cfg: var CliCfg) =
     if count > 1:
       cfg.err "more than one positional argument is variadic"
 
+  if InferShort in cfg.settings:
+    inferShortFlags cfg
+
 func parseCliFlags(cfg: var  CliCfg, node: NimNode) =
   var group: string
   expectKind node, nnkStmtList
@@ -613,9 +633,6 @@ func postPropagateCheck(c: CliCfg) =
       if f.short in short:
         let conflict = short[f.short]
         c.err "conflicting short flags for: " & f.name & " and " & conflict.name
-        # hwylCliImplError c, (
-        #   "conflicting short flags for: " & f.name & " and " & conflict.name
-        # )
 
       else:
         short[f.short] = f

tests/cli/clis/inferShort.nim

@@ -0,0 +1,25 @@
+import std/strformat
+import hwylterm, hwylterm/hwylcli
+
+hwylCli:
+  name "inferred short flags"
+  settings InferShort
+  flags:
+    input:
+      T string
+      ? "the input var"
+    output:
+      T string
+      ? "the output var"
+    count:
+      T int
+      ? "a number"
+      - n
+    nancy:
+      ? "needed a flag that starts with n :)"
+    ignore:
+      S NoShort
+      ? "a flag to not infer"
+  run:
+    echo fmt"{input=}, {output=}, {count=}, {nancy=}, {ignore=}"
+

tests/cli/tester.nim

@@ -114,3 +114,6 @@ inside sub c
   failWithArgs(
     "errorOverride", "--flag","override the default error\nerror unknown flag: flag"
   )
+  okWithArgs(
+    "inferShort", "-i input -o output","""input=input, output=output, count=0, nancy=false, ignore=false"""
+  )