lang: ast, interfaces, interpolate: Remove the legacy pos

This ports things to the new textarea. We need to plumb through things a
lot more, especially the string interpolation math to get the right
offsets everywhere, but that's coming.

lang/interfaces/ast.go

@@ -231,7 +231,7 @@ type Data struct {
 	// StrInterpolater is a function that needs to get passed in to run the
 	// string interpolation. This is passed in this way to avoid dependency
 	// cycles.
-	StrInterpolater func(string, *Pos, *Data) (Expr, error)
+	StrInterpolater func(string, *Textarea, *Data) (Expr, error)
 
 	// SourceFinder is a function that returns the contents of a source file
 	// when requested by filename. This data is used to annotate error

lang/interfaces/parser.go

@@ -1,39 +0,0 @@
-// Mgmt
-// Copyright (C) James Shubin and the project contributors
-// Written by James Shubin <james@shubin.ca> and the project contributors
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-//
-// Additional permission under GNU GPL version 3 section 7
-//
-// If you modify this program, or any covered work, by linking or combining it
-// with embedded mcl code and modules (and that the embedded mcl code and
-// modules which link with this program, contain a copy of their source code in
-// the authoritative form) containing parts covered by the terms of any other
-// license, the licensors of this program grant you additional permission to
-// convey the resulting work. Furthermore, the licensors of this program grant
-// the original author, James Shubin, additional permission to update this
-// additional permission if he deems it necessary to achieve the goals of this
-// additional permission.
-
-package interfaces
-
-// Pos represents a position in the code. This is used by the parser and string
-// interpolation.
-// TODO: consider expanding with range characteristics.
-type Pos struct {
-	Line     int    // line number starting at 1
-	Column   int    // column number starting at 1
-	Filename string // optional source filename, if known
-}