Implement filestream:lines and io.lines

docs/pages/differences.md

@@ -68,7 +68,7 @@ Nelua has additional functions in this library. See [here](/libraries/#io).
 | `io.close`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
 | `io.flush`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
 | `io.input`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
-| `io.lines`{:.language-nelua} | ❌ | `io`{:.language-nelua} |  |
+| `io.lines`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
 | `io.open`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
 | `io.output`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
 | `io.popen`{:.language-nelua} | ❌ | `io`{:.language-nelua} |  |
@@ -79,13 +79,13 @@ Nelua has additional functions in this library. See [here](/libraries/#io).
 | `io.tmpfile`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
 | `io.type`{:.language-nelua} | ✔ | `io`{:.language-nelua} |  |
 | `io.write`{:.language-nelua} | ✔ | `io`{:.language-nelua} | Doesn't support multiple arguments. |
-| `file:close`{:.language-nelua} | ✔ | `filesystem`{:.language-nelua} |  |
-| `file:flush`{:.language-nelua} | ✔ | `filesystem`{:.language-nelua} |  |
-| `file:lines`{:.language-nelua} | ✔ | `filesystem`{:.language-nelua} |  |
-| `file:read`{:.language-nelua} | ✔ | `filesystem`{:.language-nelua} | Doesn't support `*n` format and multiple arguments. |
-| `file:seek`{:.language-nelua} | ✔ | `filesystem`{:.language-nelua} |  |
-| `file:setvbuf`{:.language-nelua} | ✔ | `filesystem`{:.language-nelua} |  |
-| `file:write`{:.language-nelua} | ✔ | `filesystem`{:.language-nelua} | Doesn't support multiple arguments. Doesn't return the file itself. |
+| `file:close`{:.language-nelua} | ✔ | `filestream`{:.language-nelua} |  |
+| `file:flush`{:.language-nelua} | ✔ | `filestream`{:.language-nelua} |  |
+| `file:lines`{:.language-nelua} | ✔ | `filestream`{:.language-nelua} |  |
+| `file:read`{:.language-nelua} | ✔ | `filestream`{:.language-nelua} | Doesn't support `*n` format and multiple arguments. |
+| `file:seek`{:.language-nelua} | ✔ | `filestream`{:.language-nelua} |  |
+| `file:setvbuf`{:.language-nelua} | ✔ | `filestream`{:.language-nelua} |  |
+| `file:write`{:.language-nelua} | ✔ | `filestream`{:.language-nelua} | Doesn't support multiple arguments. Doesn't return the file itself. |
 {: .table.table-bordered.table-striped.table-sm}
 
 ## Math

lib/filestream.nelua

@@ -64,7 +64,7 @@ function filestream:_get_fp(): FILEptr
 end
 
 function filestream.open(filename: stringview, mode: facultative(stringview)) : (filestream, stringview, integer)
-  ## if mode.type.is_nil then
+  ## if mode.type.is_niltype then
   local mode: stringview = "r"
   ## end
   --TODO: check modes
@@ -212,6 +212,11 @@ function filestream:read(fmt: overload(integer,stringview,niltype)): (string, st
   if success then
     s = sb:promotestring()
   else
+    if #errmsg == 0 then
+      -- should be eof
+      errmsg = 'eof'
+      status = EOF
+    end
     sb:destroy()
   end
   return s, errmsg, status
@@ -229,6 +234,21 @@ function filestream:write(s: stringview): (boolean, stringview, integer)
   return fileresult(false)
 end
 
+function filestream:lines(fmt: overload(integer,stringview,niltype))
+  ## if fmt.type.is_niltype then
+  local fmt: stringview = 'l'
+  ## end
+  local LinesState = @record {
+    file: filestream,
+    fmt: #[fmt.type]#
+  }
+  local function lines_next(state: LinesState, prevstr: string): (boolean, string)
+    local str: string, errmsg: stringview, status: integer = state.file:read(state.fmt)
+    return status == 0, str
+  end
+  return lines_next, (@LinesState){file=$self,fmt=fmt}, (@string){}
+end
+
 function filestream:isopen(): boolean
   return pool:has(self.id)
 end
@@ -241,5 +261,3 @@ function filestream:__tostring(): string
     return string.format('file (%p)', fp)
   end
 end
-
--- TODO: filestream:lines

lib/io.nelua

@@ -101,5 +101,17 @@ function io.isopen(file: filestream): boolean
   return file:isopen()
 end
 
--- TODO: io.lines
+function io.lines(filename: facultative(stringview), fmt: overload(integer,stringview,niltype))
+  ## if filename.type.is_niltype then
+    return io.stdin:lines()
+  ## else
+    -- TODO: close file using to be closed variables
+    local file: filestream = io.open(filename)
+    if not file:isopen() then
+      error('io.lines: cannot open file')
+    end
+    return file:lines(fmt)
+  ## end
+end
+
 -- TODO: io.popen

lib/span.nelua

@@ -52,7 +52,7 @@
     ## else
       self.data = &values[#[values.type.subtype.is_sequence and 1 or 0]#]
       self.size = (@usize)(#$values)
-      ## end
+    ## end
     return self
   end
 

tests/io_test.nelua

@@ -91,11 +91,57 @@ do -- filestream:read, filestream:write and filestream:seek
   assert(file:read('a') == text)
   assert(file:close())
   assert(not file:isopen())
+end
+
+do -- filestream:lines
+  file = io.open('test.tmp', 'r')
+  local i = 1
+  for line in file:lines() do
+    assert(line == ('line'..i))
+    i = i + 1
+  end
+
+  file:seek('set')
+  i = 1
+  for line in file:lines('L') do
+    assert(line == ('line'..i..'\n'))
+    i = i + 1
+  end
+
+  file:seek('set')
+  i = 1
+  for line in file:lines(6) do
+    assert(line == ('line'..i..'\n'))
+    i = i + 1
+  end
+
+  file:close()
+end
+
+do -- io.lines
+  local i = 1
+  for line in io.lines('test.tmp') do
+    assert(line == ('line'..i))
+    i = i + 1
+  end
+
+  i = 1
+  for line in io.lines('test.tmp', 'L') do
+    assert(line == ('line'..i..'\n'))
+    i = i + 1
+  end
+
+  i = 1
+  for line in io.lines('test.tmp', 6) do
+    assert(line == ('line'..i..'\n'))
+    i = i + 1
+  end
 
   os.remove('test.tmp')
 end
 
 do -- filestream:setvbuf
+  os.remove('test.tmp')
   file = io.open('test.tmp', 'w')
   assert(file:isopen())
   assert(file:setvbuf("no") == true)