Add path.janet.

auxbin/jpm

@@ -31,8 +31,10 @@ Keys are:
 (def todo @[])
 (each arg args
   (if (string/has-prefix? "--" arg)
-    (let [[key value] (peg/match argpeg arg)]
-      (setdyn (keyword key) value))
+    (if-let [m (peg/match argpeg arg)]
+      (let [[key value] m]
+        (setdyn (keyword key) value))
+      (print "invalid argument " arg))
     (array/push todo arg)))
 
 (cook/import-rules "./project.janet")

auxlib/path.janet

@@ -0,0 +1,149 @@
+### path.janet
+###
+### A library for path manipulation.
+###
+### Copyright 2019 © Calvin Rose
+
+#
+# Common
+#
+
+(def- ext-peg
+  (peg/compile ~{:back (> -1 (+ (* ($) (set "\\/.")) :back))
+                 :main :back}))
+
+(defn ext
+  "Get the file extension for a path."
+  [path]
+  (if-let [m (peg/match ext-peg path (length path))]
+    (let [i (m 0)]
+      (if (= (path i) 46)
+        (string/slice path (m 0) -1)))))
+
+(defn- redef
+  "Redef a value, keeping all metadata."
+  [from to]
+  (setdyn (symbol to) (dyn (symbol from))))
+
+#
+# Generating Macros
+#
+
+(defmacro- decl-sep [pre sep] ~(def ,(symbol pre "/sep") ,sep))
+(defmacro- decl-delim [pre d] ~(def ,(symbol pre "/delim") ,d))
+
+(defmacro- decl-last-sep
+  [pre sep]
+  ~(def- ,(symbol pre "/last-sep-peg")
+    (peg/compile ~{:back (> -1 (+ (* ,sep ($)) :back))
+                   :main :back})))
+
+(defmacro- decl-basename
+  [pre]
+  ~(defn ,(symbol pre "/basename")
+    "Gets the base file name of a path."
+    [path]
+    (if-let [m (peg/match
+                 ,(symbol pre "/last-sep-peg")
+                 path
+                 (length path))]
+      (let [[p] m]
+        (string/slice path p -1))
+      path)))
+
+(defmacro- decl-parts
+  [pre sep]
+  ~(defn ,(symbol pre "/parts")
+     "Split a path into its parts."
+     [path]
+     (string/split ,sep path)))
+
+(defmacro- decl-normalize
+  [pre sep lead]
+  ~(defn ,(symbol pre "/normalize")
+     "Normalize a path. This removes . and .. in the
+     path, as well as empty path elements."
+     [path]
+     (def els (string/split ,sep path))
+     (def newparts @[])
+     (if (,(symbol pre "/abspath?") path) (array/push newparts ,lead))
+     (each part els
+       (case part
+         "" nil
+         "." nil
+         ".." (array/pop newparts)
+         (array/push newparts part)))
+     (string/join newparts ,sep)))
+
+(defmacro- decl-join
+  [pre sep]
+  ~(defn ,(symbol pre "/join")
+     "Join path elements together."
+     [& els]
+     (,(symbol pre "/normalize") (string/join els ,sep))))
+
+(defmacro- decl-abspath
+  [pre]
+  ~(defn ,(symbol pre "/abspath")
+     "Coerce a path to be absolute."
+     [path]
+     (if (,(symbol pre "/abspath?") path)
+       path
+       (,(symbol pre "/join") (os/cwd) path))))
+
+#
+# Posix
+#
+
+(defn posix/abspath?
+  "Check if a path is absolute."
+  [path]
+  (string/has-prefix? "/" path))
+
+(redef "ext" "posix/ext")
+(decl-sep "posix" "/")
+(decl-delim "posix" ";")
+(decl-last-sep "posix" "/")
+(decl-basename "posix")
+(decl-parts "posix" "/")
+(decl-normalize "posix" "/" "")
+(decl-join "posix" "/")
+(decl-abspath "posix")
+
+#
+# Windows
+#
+
+(def- abs-peg (peg/compile '(* (range "AZ") ":\\")))
+(defn win32/abspath?
+  "Check if a path is absolute."
+  [path]
+  (peg/match abs-peg path))
+
+(redef "ext" "win32/ext")
+(decl-sep "win32" "\\")
+(decl-delim "win32" ":")
+(decl-last-sep "win32" "\\")
+(decl-basename "win32")
+(decl-parts "win32" "\\")
+(decl-normalize "win32" "\\" "C:")
+(decl-join "win32" "\\")
+(decl-abspath "win32")
+
+#
+# Specialize for current OS
+#
+
+(def- syms
+  ["ext"
+   "sep"
+   "delim"
+   "basename"
+   "abspath?"
+   "abspath"
+   "parts"
+   "normalize"
+   "join"])
+(let [pre (if (= :windows (os/which)) "win32" "posix")]
+  (each sym syms
+    (redef (string pre "/" sym) sym)))