IsAssign bool            // The variables are being assigned, not declared.
	Decl     []*VariableNode // Variables in lexical order.
	Cmds     []*CommandNode  // The commands in lexical order.
}

func (t *Tree) newPipeline(pos Pos, line int, vars []*VariableNode) *PipeNode {
	return &PipeNode{tr: t, NodeType: NodePipe, Pos: pos, Line: line, Decl: vars}
}

func (p *PipeNode) append(command *CommandNode) {
	p.Cmds = append(p.Cmds, command)

	return t.newContinue(pos, line)
}

// Pipeline:
//
//	declarations? command ('|' command)*
func (t *Tree) pipeline(context string, end itemType) (pipe *PipeNode) {
	token := t.peekNonSpace()
	pipe = t.newPipeline(token.pos, token.line, nil)
	// Are there declarations or assignments?
decls:
	if v := t.peekNonSpace(); v.typ == itemVariable {
		t.next()