Fix #88.

src/CST.ml

@@ -325,6 +325,7 @@ and word_component =
   | WordAssignmentWord of assignment_word
   | WordDoubleQuoted of word
   | WordSingleQuoted of word
+  | WordTildePrefix of string
   | WordLiteral of string
   | WordVariable of variable
   | WordGlobAll   (* asterisk *)

src/prelexerState.ml

@@ -384,6 +384,7 @@ let return ?(with_newline=false) lexbuf (current : prelexer_state) tokens =
             | QuotingMark _ -> []
          ) (buffer current)))
       in
+      let csts = TildePrefix.recognize csts in
       [Pretoken.PreWord (w, csts)]
   in
   let tokens = if with_newline then tokens @ [Pretoken.NEWLINE] else tokens in

src/tildePrefix.ml

@@ -0,0 +1,63 @@
+(**************************************************************************)
+(*  -*- tuareg -*-                                                        *)
+(*                                                                        *)
+(*  Copyright (C) 2017,2018,2019 Yann Régis-Gianas, Nicolas Jeannerod,    *)
+(*  Ralf Treinen.                                                         *)
+(*                                                                        *)
+(*  This is free software: you can redistribute it and/or modify it       *)
+(*  under the terms of the GNU General Public License, version 3.         *)
+(*                                                                        *)
+(*  Additional terms apply, due to the reproduction of portions of        *)
+(*  the POSIX standard. Please refer to the file COPYING for details.     *)
+(**************************************************************************)
+
+(*specification
+
+  A "tilde-prefix" consists of an unquoted <tilde> character at the
+   beginning of a word, followed by all of the characters preceding
+   the first unquoted <slash> in the word, or all the characters in
+   the word if there is no <slash>. In an assignment (see XBD Variable
+   Assignment), multiple tilde-prefixes can be used: at the beginning
+   of the word (that is, following the <equals-sign> of the
+   assignment), following any unquoted <colon>, or both. A
+   tilde-prefix in an assignment is terminated by the first unquoted
+   <colon> or <slash>. If none of the characters in the tilde-prefix
+   are quoted, the characters in the tilde-prefix following the
+   <tilde> are treated as a possible login name from the user
+   database. A portable login name cannot contain characters outside
+   the set given in the description of the LOGNAME environment
+   variable in XBD Other Environment Variables. If the login name is
+   null (that is, the tilde-prefix contains only the tilde), the
+   tilde-prefix is replaced by the value of the variable HOME. If HOME
+   is unset, the results are unspecified. Otherwise, the tilde-prefix
+   shall be replaced by a pathname of the initial working directory
+   associated with the login name obtained using the getpwnam()
+   function as defined in the System Interfaces volume of
+   POSIX.1-2017. If the system does not recognize the login name, the
+   results are undefined.
+
+*)
+open CST
+
+let find_login s =
+  match Str.(split (regexp "/") s) with
+  | login :: rem -> [WordTildePrefix login; WordLiteral (String.concat "/" rem)]
+  | _ -> assert false (* Because there is slash, or not. *)
+
+let rec make_tilde_prefix_explicit rhs_assignment = function
+  | (WordLiteral s) as cst when s <> "" ->
+     if s.[0] = '~' then (
+       if rhs_assignment then
+         let s = Str.(split (regexp ":") s) in
+         List.(flatten (map find_login s))
+       else
+         find_login s
+     ) else [cst]
+  | WordAssignmentWord (name, Word (s, csts)) ->
+     let csts = recognize ~rhs_assignment:true csts in
+     [WordAssignmentWord (name, Word (s, csts))]
+  | cst ->
+     [cst]
+
+and recognize ?(rhs_assignment=false) csts =
+  List.(flatten (map (make_tilde_prefix_explicit rhs_assignment) csts))

tests/good/2.6-word-expansions/2.6.1-tilde-prefix/login.sh

@@ -0,0 +1,2 @@
+echo ~knuth/foo/bar
+X=~kn:~/bin:~darkvador/secret

tests/good/2.6-word-expansions/2.6.1-tilde-prefix/login.sh.expected

@@ -0,0 +1,87 @@
+[
+  "Program_LineBreak_CompleteCommands_LineBreak",
+  [ "LineBreak_Empty" ],
+  [
+    "CompleteCommands_CompleteCommands_NewlineList_CompleteCommand",
+    [
+      "CompleteCommands_CompleteCommand",
+      [
+        "CompleteCommand_CList",
+        [
+          "CList_AndOr",
+          [
+            "AndOr_Pipeline",
+            [
+              "Pipeline_PipeSequence",
+              [
+                "PipeSequence_Command",
+                [
+                  "Command_SimpleCommand",
+                  [
+                    "SimpleCommand_CmdName_CmdSuffix",
+                    [
+                      "CmdName_Word",
+                      [ "Word", "echo", [ [ "WordName", "echo" ] ] ]
+                    ],
+                    [
+                      "CmdSuffix_Word",
+                      [
+                        "Word",
+                        "~knuth/foo/bar",
+                        [
+                          [ "WordTildePrefix", "~knuth" ],
+                          [ "WordLiteral", "foo/bar" ]
+                        ]
+                      ]
+                    ]
+                  ]
+                ]
+              ]
+            ]
+          ]
+        ]
+      ]
+    ],
+    [ "NewLineList_NewLine" ],
+    [
+      "CompleteCommand_CList",
+      [
+        "CList_AndOr",
+        [
+          "AndOr_Pipeline",
+          [
+            "Pipeline_PipeSequence",
+            [
+              "PipeSequence_Command",
+              [
+                "Command_SimpleCommand",
+                [
+                  "SimpleCommand_CmdPrefix",
+                  [
+                    "CmdPrefix_AssignmentWord",
+                    [
+                      [ "Name", "X" ],
+                      [
+                        "Word",
+                        "~kn:~/bin:~darkvador/secret",
+                        [
+                          [ "WordTildePrefix", "~kn" ],
+                          [ "WordLiteral", "" ],
+                          [ "WordTildePrefix", "~" ],
+                          [ "WordLiteral", "bin" ],
+                          [ "WordTildePrefix", "~darkvador" ],
+                          [ "WordLiteral", "secret" ]
+                        ]
+                      ]
+                    ]
+                  ]
+                ]
+              ]
+            ]
+          ]
+        ]
+      ]
+    ]
+  ],
+  [ "LineBreak_Empty" ]
+]