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/ast/structs.go

@@ -7495,14 +7495,6 @@ func (obj *ExprStr) Init(data *interfaces.Data) error {
 // which need interpolation. If any are found, it returns a larger AST which has
 // a function which returns a string as its root. Otherwise it returns itself.
 func (obj *ExprStr) Interpolate() (interfaces.Expr, error) {
-	pos := &interfaces.Pos{
-		// XXX: populate this?
-		// column/line number, starting at 1
-		//Column: -1, // TODO
-		//Line: -1, // TODO
-		//Filename: "", // optional source filename, if known
-	}
-
 	data := &interfaces.Data{
 		// TODO: add missing fields here if/when needed
 		Fs:       obj.data.Fs,
@@ -7526,7 +7518,7 @@ func (obj *ExprStr) Interpolate() (interfaces.Expr, error) {
 		},
 	}
 
-	result, err := obj.data.StrInterpolater(obj.V, pos, data)
+	result, err := obj.data.StrInterpolater(obj.V, &obj.Textarea, data)
 	if err != nil {
 		return nil, err
 	}

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
-}

lang/interpolate/interpolate.go

@@ -57,21 +57,21 @@ const (
 
 // StrInterpolate interpolates a string and returns the representative AST. If
 // there was nothing to interpolate, this returns (nil, nil).
-func StrInterpolate(str string, pos *interfaces.Pos, data *interfaces.Data) (interfaces.Expr, error) {
+func StrInterpolate(str string, textarea *interfaces.Textarea, data *interfaces.Data) (interfaces.Expr, error) {
 	if data.Debug {
 		data.Logf("interpolating: %s", str)
 	}
 
 	if UseHilInterpolation {
-		return HilInterpolate(str, pos, data)
+		return HilInterpolate(str, textarea, data)
 	}
-	return RagelInterpolate(str, pos, data)
+	return RagelInterpolate(str, textarea, data)
 }
 
 // RagelInterpolate interpolates a string and returns the representative AST. It
 // uses the ragel parser to perform the string interpolation. If there was
 // nothing to interpolate, this returns (nil, nil).
-func RagelInterpolate(str string, pos *interfaces.Pos, data *interfaces.Data) (interfaces.Expr, error) {
+func RagelInterpolate(str string, textarea *interfaces.Textarea, data *interfaces.Data) (interfaces.Expr, error) {
 	sequence, err := Parse(str)
 	if err != nil {
 		return nil, errwrap.Wrapf(err, "parser failed")
@@ -125,13 +125,14 @@ func RagelInterpolate(str string, pos *interfaces.Pos, data *interfaces.Data) (i
 
 // HilInterpolate interpolates a string and returns the representative AST. This
 // particular implementation uses the hashicorp hil library and syntax to do so.
-func HilInterpolate(str string, pos *interfaces.Pos, data *interfaces.Data) (interfaces.Expr, error) {
+func HilInterpolate(str string, textarea *interfaces.Textarea, data *interfaces.Data) (interfaces.Expr, error) {
 	var line, column int = -1, -1
 	var filename string
-	if pos != nil {
+	if textarea != nil {
-		line = pos.Line
+		startLine, startColumn := textarea.Pos() // zero based
-		column = pos.Column
+		line = startLine
-		filename = pos.Filename
+		column = startColumn
+		filename = textarea.Filename() // TODO: .Path() instead?
 	}
 	hilPos := hilast.Pos{
 		Line:     line,