...(compound_word
  parts: [
    (Token
      id: Id.Lit_Chars
      col: 0
      length: 2
      span_id: 0
      line: (SourceLine line_num:1 content:'hi\'\n' src:(source.MainFile path:hi))
      tval: hi
    )
    (single_quoted
      left: 
        (Token
          id: Id.Left_SingleQuote
          col: 2
          length: 1
          span_id: 1
          line: (SourceLine line_num:1 content:'hi\'\n' src:(source.MainFile path:hi))
          tval: '\''
        )
      tokens: [
        (Token
          id: Id.Lit_Chars
          col: 3
          length: 1
          span_id: 2
          line: (SourceLine line_num:1 content:'hi\'\n' src:(source.MainFile path:hi))
          tval: '\n'
        )
        (Token
          id: Id.Lit_Chars
          col: 0
          length: 13
          span_id: 3
          line: 
            (SourceLine
              line_num: 2
              content: 'single quoted\'"double\n'
              src: (source.MainFile path:hi)
            )
          tval: 'single quoted'
        )
      ]
      right: 
        (Token
          id: Id.Right_SingleQuote
          col: 13
          length: 1
          span_id: 4
          line: 
            (SourceLine
              line_num: 2
              content: 'single quoted\'"double\n'
              src: (source.MainFile path:hi)
            )
          tval: '\''
        )
    )
    (double_quoted
      left: 
        (Token
          id: Id.Left_DoubleQuote
          col: 14
          length: 1
          span_id: 5
          line: 
            (SourceLine
              line_num: 2
              content: 'single quoted\'"double\n'
              src: (source.MainFile path:hi)
            )
          tval: '"'
        )
      parts: [
        (Token
          id: Id.Lit_Chars
          col: 15
          length: 7
          span_id: 6
          line: 
            (SourceLine
              line_num: 2
              content: 'single quoted\'"double\n'
              src: (source.MainFile path:hi)
            )
          tval: 'double\n'
        )
        (Token
          id: Id.Lit_Chars
          col: 0
          length: 7
          span_id: 7
          line: (SourceLine line_num:3 content:'quoted\n' src:(source.MainFile path:hi))
          tval: 'quoted\n'
        )
      ]
      right: 
        (Token
          id: Id.Right_DoubleQuote
          col: 0
          length: 1
          span_id: 8
          line: (SourceLine line_num:4 content:'"there\n' src:(source.MainFile path:hi))
          tval: '"'
        )
    )
    (Token
      id: Id.Lit_Chars
      col: 1
      length: 5
      span_id: 9
      line: (SourceLine line_num:4 content:'"there\n' src:(source.MainFile path:hi))
      tval: there
    )
  ]
)
s = '\'\nsingle quoted\'"double\nquoted\n"'
s = "'\nsingle quoted'"
s = 'hi'
(compound_word
  parts: [
    (Token
      id: Id.Lit_VarLike
      col: 4
      length: 4
      span_id: 3
      line: (SourceLine line_num:1 content:'ls; foo=42' src:(source.MainFile path:''))
      tval: 'foo='
    )
    (Token
      id: Id.Lit_Chars
      col: 8
      length: 2
      span_id: 4
      line: (SourceLine line_num:1 content:'ls; foo=42' src:(source.MainFile path:''))
      tval: 42
    )
  ]
)
(compound_word
  parts: [
    (Token
      id: Id.Lit_VarLike
      col: 4
      length: 5
      span_id: 9
      line: (SourceLine line_num:1 content:'ls; foo+=X' src:(source.MainFile path:''))
      tval: 'foo+='
    )
    (Token
      id: Id.Lit_Chars
      col: 9
      length: 1
      span_id: 10
      line: (SourceLine line_num:1 content:'ls; foo+=X' src:(source.MainFile path:''))
      tval: X
    )
  ]
)
('\n---', '${array[0]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    bracket_op: (bracket_op.ArrayIndex expr:{<Id.Lit_Digits 0>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${array[5+5]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    bracket_op: 
      (bracket_op.ArrayIndex
        expr: 
          (arith_expr.Binary
       ....     op_id: Id.Arith_Plus
            left: {<Id.Lit_Digits 5>}
            right: {<Id.Lit_Digits 5>}
          )
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${array[@]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    bracket_op: (bracket_op.WholeArray op_id:Id.Lit_At)
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${array[*]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    bracket_op: (bracket_op.WholeArray op_id:Id.Arith_Star)
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${#}')
{(${ Id.VSub_Pound '#')}('\n---', '${!}')
{(${ Id.VSub_Bang '!')}('\n---', '${?}')
{(${ Id.VSub_QMark '?')}('\n---', '${var}')
{(${ Id.VSub_Name var)}('\n---', '${15}')
{(${ Id.VSub_Number 15)}('\n---', '${#var}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    prefix_op: <Id.VSub_Pound '#'>
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${!ref}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name ref>
    var_name: ref
    prefix_op: <Id.VSub_Bang '!'>
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${##}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Pound '#'>
    var_name: '#'
    prefix_op: <Id.VSub_Pound '#'>
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${array[0]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    bracket_op: (bracket_op.ArrayIndex expr:{<Id.Lit_Digits 0>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${array[@]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    bracket_op: (bracket_op.WholeArray op_id:Id.Lit_At)
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${#array[0]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    prefix_op: <Id.VSub_Pound '#'>
    bracket_op: (bracket_op.ArrayIndex expr:{<Id.Lit_Digits 0>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${!array[0]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    prefix_op: <Id.VSub_Bang '!'>
    bracket_op: (bracket_op.ArrayIndex expr:{<Id.Lit_Digits 0>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var#prefix}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Pound '#'> arg_word:{<prefix>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${!var#prefix}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    prefix_op: <Id.VSub_Bang '!'>
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Pound '#'> arg_word:{<prefix>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${#var#prefix}')
Got expected ParseError: 
('\n---', '${##2}')
Got expected ParseError: 
--MULTI
('\n---', '${undef:-')
Got expected ParseError: 
('\n---', '${undef:-$')
Got expected ParseError: 
('\n---', '${undef:-$F')
Got expected ParseError: 
('\n---', '${x@')
Got expected ParseError: 
('\n---', '${x@Q')
Got expected ParseError: 
('\n---', '${x%')
Got expected ParseError: 
('\n---', '${x/')
Got expected ParseError: 
('\n---', '${x/a/')
Got expected ParseError: 
('\n---', '${x/a/b')
Got expected ParseError: 
('\n---', '${x:')
Got expected ParseError: 
('\n---', '--foo=$func()')
{<--foo> <Id.Lit_Equals '='> 
  (word_part.FuncCall
    name: <Id.VSub_DollarName '$func'>
    args: (ArgList left:<Id.VSub_DollarName '$func'> positional:[] named:[] right:<Id.Op_RParen _>)
  )
}('\n---', '$func()trailer')
{
  (word_part.FuncCall
    name: <Id.VSub_DollarName '$func'>
    args: (ArgList left:<Id.VSub_DollarName '$func'> positional:[] named:[] right:<Id.Op_RParen _>)
  ) <trailer>
}('\n---', '--foo=$func()trailer')
{<--foo> <Id.Lit_Equals '='> 
  (word..._part.FuncCall
    name: <Id.VSub_DollarName '$func'>
    args: (ArgList left:<Id.VSub_DollarName '$func'> positional:[] named:[] right:<Id.Op_RParen _>)
  ) <trailer>
}('\n---', '${#@}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_At '@'>
    var_name: '@'
    prefix_op: <Id.VSub_Pound '#'>
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${#11}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Number 11>
    var_name: 11
    prefix_op: <Id.VSub_Pound '#'>
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${#str}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name str>
    var_name: str
    prefix_op: <Id.VSub_Pound '#'>
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${#array[0]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    prefix_op: <Id.VSub_Pound '#'>
    bracket_op: (bracket_op.ArrayIndex expr:{<Id.Lit_Digits 0>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${#array["key"]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    prefix_op: <Id.VSub_Pound '#'>
    bracket_op: (bracket_op.ArrayIndex expr:{(DQ <key>)})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '@words')
{(word_part.Splice name:<Id.Lit_Splice '@words'> var_name:words)}('\n---', '.@words')
{<.> <Id.Lit_Splice '@words'>}('\n---', '.@words.')
{<.> <Id.Lit_Splice '@words'> <.>}('\n---', '@words[')
Got expected ParseError: 
('\n---', '@words.')
Got expected ParseError: 
('\n---', '@func()')
{
  (word_part.FuncCall
    name: <Id.Lit_Splice '@func'>
    args: (ArgList left:<Id.Lit_Splice '@func'> positional:[] named:[] right:<Id.Op_RParen _>)
  )
}('\n---', '$(echo @func())')
{
  (command_sub
    left_token: <Id.Left_DollarParen '$('>
    child: 
      (C {<echo>} 
        {
          (word_part.FuncCall
            name: <Id.Lit_Splice '@func'>
            args: (ArgList left:<Id.Lit_Splice '@func'> positional:[] named:[] right:<Id.Op_RParen _>)
          )
        }
      )
    right: <Id.Eof_RParen _>
  )
}('\n---', '$(($(echo @func())))')
{
  (word_part.ArithSub
    anode: 
      {
        (command_sub
          left_token: <Id.Left_DollarParen '$('>
          child: 
            (C {<echo>} 
              {
                (word_part.FuncCall
                  name: <Id.Lit_Splice '@func'>
                  args: 
                    (ArgList
                      left: <Id.Lit_Splice '@func'>
                      positional: []
                      named: []
                      right: <Id.Op_RParen _>
                    )
                )
              }
            )
          right: <Id.Eof_RParen _>
        )
      }
  )
}('\n---', '@func().')
Got expected ParseError: 
{<Id.Lit_VarLike 'a='> (sh_array_literal left:<Id.Op_LParen _> words:[{<1>} {<2>} {<3>}])}a=(1 2 3)
0
(Token
  id: Id.Lit_VarLike
  col: 0
  length: 2
  span_id: 0
  line: (SourceLine line_num:1 content:'a=(1 2 3)' src:(source.MainFile path:word_parse_test.py))
  tval: 'a='
)
{<foo>}foo
0
(Token
  id: Id.Lit_Chars
  col: 0
  length: 3
  span_id: 0
  line: (SourceLine line_num:1 content:foo src:(source.MainFile path:word_parse_test.py))
  tval: foo
)
{(word_part.EscapedLiteral token:<Id.Lit_EscapedChar '\\$'> ch:'$')}\$
0
(Token
  id: Id.Lit_EscapedChar
  col: 0
  length: 2
  span_id: 0
  line: (SourceLine line_num:1 content:'\\$' src:(source.MainFile path:word_parse_test.py))
  tval: '\\$'
)
{(SQ )}''
0
(Token
  id: Id.Left_SingleQuote
  col: 0
  length: 1
  span_id: 0
  line: (SourceLine line_num:1 content:'\'\'' src:(source.MainFile path:word_parse_test.py))
  tval: '\''
)
{(SQ <sq>)}'sq'
0
(Token
  id: Id.Left_SingleQuote
  col: 0
  length: 1
  span_id: 0
  line: (SourceLine line_num:1 content:'\'sq\'' src:(source.MainFile path:word_parse_test.py))
  tval: '\''
)
{(DQ )}""
0
(Token
  id: Id.Left_DoubleQuote
  col: 0
  length: 1
  span_id: 0
  line: (SourceLine line_num:1 content:'""' src:(source.MainFile path:word_parse_te.st.py))
  tval: '"'
)
{(DQ <dq>)}"dq"
0
(Token
  id: Id.Left_DoubleQuote
  col: 0
  length: 1
  span_id: 0
  line: (SourceLine line_num:1 content:'"dq"' src:(source.MainFile path:word_parse_test.py))
  tval: '"'
)
{
  (command_sub
    left_token: <Id.Left_DollarParen '$('>
    child: (C {<echo>} {<command>} {<sub>})
    right: <Id.Eof_RParen _>
  )
}$(echo command sub)
0
(Token
  id: Id.Left_DollarParen
  col: 0
  length: 2
  span_id: 0
  line: 
    (SourceLine
      line_num: 1
      content: '$(echo command sub)'
      src: (source.MainFile path:word_parse_test.py)
    )
  tval: '$('
)
{
  (word_part.ArithSub
    anode: (arith_expr.Binary op_id:Id.Arith_Plus left:{<Id.Lit_Digits 1>} right:{<Id.Lit_Digits 2>})
  )
}$(( 1 + 2 ))
0
(Token
  id: Id.Left_DollarDParen
  col: 0
  length: 3
  span_id: 0
  line: (SourceLine line_num:1 content:'$(( 1 + 2 ))' src:(source.MainFile path:word_parse_test.py))
  tval: '$(('
)
{<Id.Lit_TildeLike '~user'>}~user
0
(Token
  id: Id.Lit_TildeLike
  col: 0
  length: 5
  span_id: 0
  line: (SourceLine line_num:1 content:'~user' src:(source.MainFile path:word_parse_test.py))
  tval: '~user'
)
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Pound '#'> arg_word:{})
    right: <Id.Right_DollarBrace '}'>
  )
}${var#}
0
(Token
  id: Id.Left_DollarBrace
  col: 0
  length: 2
  span_id: 0
  line: (SourceLine line_num:1 content:'${var#}' src:(source.MainFile path:word_parse_test.py))
  tval: '${'
)
('\n---', '${var/pat/replace}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: {<replace>}
        replace_mode: Id.Undefined_Tok
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var//pat/replace}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: {<replace>}
        replace_mode: Id.Lit_Slash
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var/%pat/replace}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: {<replace>}
        replace_mode: Id.Lit_Percent
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var/#pat/replace}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: {<replace>}
        replace_mode: Id.Lit_Pound
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var/pat}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: (rhs_word.Empty)
        replace_mode: Id.Undefined_Tok
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var//pat}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: (rhs_word.Empty)
        replace_mode: Id.Lit_Slash
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var/pat//}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: {<Id.Lit_Slash '/'>}
        replace_mode: Id.Undefined_Tok
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var/pat///}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    t..oken: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: {<Id.Lit_Slash '/'> <Id.Lit_Slash '/'>}
        replace_mode: Id.Undefined_Tok
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var/pat/"//"}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<pat>}
        replace: {(DQ <'//'>)}
        replace_mode: Id.Undefined_Tok
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var////\\\\/}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: 
      (suffix_op.PatSub
        pat: {<Id.Lit_Slash '/'>}
        replace: 
          {(word_part.EscapedLiteral token:<Id.Lit_EscapedChar '\\\\'> ch:'\\') <Id.Lit_Slash '/'>}
        replace_mode: Id.Lit_Slash
        slash_tok: <Id.VOp2_Slash _>
      )
    right: <Id.Right_DollarBrace '}'>
  )
}---
ls "foo"
()
{<ls>}{(DQ <foo>)}<Id.Eof_Real ''>---
$(( 1 + 2 ))
()
{
  (word_part.ArithSub
    anode: (arith_expr.Binary op_id:Id.Arith_Plus left:{<Id.Lit_Digits 1>} right:{<Id.Lit_Digits 2>})
  )
}<Id.Eof_Real ''>---
$(echo $(( 1 )) )
()
{
  (command_sub
    left_token: <Id.Left_DollarParen '$('>
    child: (C {<echo>} {(word_part.ArithSub anode:{<Id.Lit_Digits 1>})})
    right: <Id.Eof_RParen _>
  )
}<Id.Eof_Real ''>---
echo ${#array[@]} b
()
{<echo>}{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    prefix_op: <Id.VSub_Pound '#'>
    bracket_op: (bracket_op.WholeArray op_id:Id.Lit_At)
    right: <Id.Right_DollarBrace '}'>
  )
}{<b>}<Id.Eof_Real ''>---
echo $(( ${#array[@]} ))
()
{<echo>}{
  (word_part.ArithSub
    anode: 
      {
        (braced_var_sub
          left: <Id.Left_DollarBrace '${'>
          token: <Id.VSub_Name array>
          var_name: array
          prefix_op: <Id.VSub_Pound '#'>
          bracket_op: (bracket_op.WholeArray op_id:Id.Lit_At)
          right: <Id.Right_DollarBrace '}'>
        )
      }
  )
}<Id.Eof_Real ''>---
echo ${@%suffix}
()
{<echo>}{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_At '@'>
    var_name: '@'
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Percent '%'> arg_word:{<suffix>})
    right: <Id.Right_DollarBrace '}'>
  )
}<Id.Eof_Real ''>---
${@}
()
{(${ Id.VSub_At '@')}<Id.Eof_Real ''>---
echo ${var,,}
()
{<echo>}{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_DComma ',,'> arg_word:{})
    right: <Id.Right_DollarBrace '}'>
  )
}<Id.Eof_Real ''>---
echo ${var,,?}
()
{<echo>}{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_DComma ',,'> arg_word:{<Id.Lit_Other '?'>})
    right: <Id.Right_DollarBrace '}'>
  )
}<Id.Eof_Real ''>---
${\
foo}
()
{(${ Id.VSub_Name foo)}<Id.Eof_Real ''>---
${foo\
}
()
{(${ Id.VSub_Name foo)}<Id.Eof_Real ''>---
${foo#\
yo}
()
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name foo>
    var_name: foo
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Pound '#'> arg_word:{<yo>})
    right: <Id.Right_DollarBrace '}'>
  )
}<Id.Eof_Real ''>---
"${foo#\
yo}"
()
{
  (DQ 
    (braced_var_sub
      left: <Id.Left_DollarBrace '${'>
      token: <Id.VSub_Name foo>
      var_name: foo
      suffix_op: (suffix_op.Unary op:<Id.VOp1_Pound '#'> arg_word:{<yo>})
      right: <Id.Right_DollarBrace '}'>
    )
  )
}<Id.Eof_Real ''>---
1 + 2
()
{<Id.Lit_Digits 1>}<Id.Arith_Plus _>{<Id.Lit_Digits 2>}<Id.Eof_Real ''>---
a + b
()
{<Id.Lit_ArithVarLike a>}<Id.Arith_Plus _>{<Id.Lit_ArithVarLike b>}<Id.Eof_Real ''>---
$a * $b
()
{($ Id.VSub_DollarName a)}<Id.Arith_Star _>{($ Id.VSub_DollarName b)}<Id.Eof_Real ''>---
${a} * ${b}
()
{(${ Id.VSub_Name a)}<Id.Arith_Star _>{(${ Id.VSub_Name b)}<Id.Eof_Re....al ''>---
$(echo 1) * $(echo 2)
()
{(command_sub left_token:<Id.Left_DollarParen '$('> child:(C {<echo>} {<1>}) right:<Id.Eof_RParen _>)}<Id.Arith_Star _>{(command_sub left_token:<Id.Left_DollarParen '$('> child:(C {<echo>} {<2>}) right:<Id.Eof_RParen _>)}<Id.Eof_Real ''>---
`echo 1` + 2
()
{
  (command_sub
    left_token: <Id.Left_Backtick '`'>
    child: (C {<echo>} {<1>})
    right: <Id.Backtick_Right '`'>
  )
}<Id.Arith_Plus _>{<Id.Lit_Digits 2>}<Id.Eof_Real ''>---
$((1 + 2)) * $((3 + 4))
()
{
  (word_part.ArithSub
    anode: (arith_expr.Binary op_id:Id.Arith_Plus left:{<Id.Lit_Digits 1>} right:{<Id.Lit_Digits 2>})
  )
}<Id.Arith_Star _>{
  (word_part.ArithSub
    anode: (arith_expr.Binary op_id:Id.Arith_Plus left:{<Id.Lit_Digits 3>} right:{<Id.Lit_Digits 4>})
  )
}<Id.Eof_Real ''>---
'single quoted'
()
{(SQ <'single quoted'>)}<Id.Eof_Real ''>---
"${a}" + "${b}"
()
{(DQ (${ Id.VSub_Name a))}<Id.Arith_Plus _>{(DQ (${ Id.VSub_Name b))}<Id.Eof_Real ''>---
$# + $$
()
{($ Id.VSub_Pound '#')}<Id.Arith_Plus _>{($ Id.VSub_Dollar '$')}<Id.Eof_Real ''>---
$(( x[0] < 5 ))
()
{
  (word_part.ArithSub
    anode: 
      (arith_expr.Binary
        op_id: Id.Arith_Less
        left: 
          (arith_expr.Binary
            op_id: Id.Arith_LBracket
            left: ($ Id.Lit_ArithVarLike x)
            right: {<Id.Lit_Digits 0>}
          )
        right: {<Id.Lit_Digits 5>}
      )
  )
}<Id.Eof_Real ''>---
$(( ++i ))
()
{
  (word_part.ArithSub
    anode: (arith_expr.UnaryAssign op_id:Id.Arith_DPlus child:($ Id.Lit_ArithVarLike i))
  )
}<Id.Eof_Real ''>---
$(( i++ ))
()
{
  (word_part.ArithSub
    anode: (arith_expr.UnaryAssign op_id:Id.Node_PostDPlus child:($ Id.Lit_ArithVarLike i))
  )
}<Id.Eof_Real ''>---
$(( x -= 1))
()
{
  (word_part.ArithSub
    anode: 
      (arith_expr.BinaryAssign
        op_id: Id.Arith_MinusEqual
        left: ($ Id.Lit_ArithVarLike x)
        right: {<Id.Lit_Digits 1>}
      )
  )
}<Id.Eof_Real ''>---
$(( x |= 1))
()
{
  (word_part.ArithSub
    anode: 
      (arith_expr.BinaryAssign
        op_id: Id.Arith_PipeEqual
        left: ($ Id.Lit_ArithVarLike x)
        right: {<Id.Lit_Digits 1>}
      )
  )
}<Id.Eof_Real ''>---
$(( x[0] = 1 ))
()
{
  (word_part.ArithSub
    anode: 
      (arith_expr.BinaryAssign
        op_id: Id.Arith_Equal
        left: 
          (arith_expr.Binary
            op_id: Id.Arith_LBracket
            left: ($ Id.Lit_ArithVarLike x)
            right: {<Id.Lit_Digits 0>}
          )
        right: {<Id.Lit_Digits 1>}
      )
  )
}<Id.Eof_Real ''>---
$(( 1 | 0 ))
()
{
  (word_part.ArithSub
    anode: (arith_expr.Binary op_id:Id.Arith_Pipe left:{<Id.Lit_Digits 1>} right:{<Id.Lit_Digits 0>})
  )
}<Id.Eof_Real ''>---
$((0x$size))
()
{(word_part.ArithSub anode:{<Id.Lit_Digits 0> <Id.Lit_ArithVarLike x> ($ Id.VSub_DollarName size)})}<Id.Eof_Real ''>('\n---', '$(( (1+2) ))')
{
  (word_part.ArithSub
    anode: (arith_expr.Binary op_id:Id.Arith_Plus left:{<Id.Lit_Digits 1>} right:{<Id.Lit_Digits 2>})
  )
}('\n---', '$(( (1+2) ))')
{
  (word_part.ArithSub
    anode: (arith_expr.Binary op_id:Id.Arith_Plus left:{<Id.Lit_Digits 1>} right:{<Id.Lit_Digits 2>})
  )
}('\n---', '${foo:0}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name foo>
    var_name: foo
    suffix_op: (suffix_op.Slice begin:{<Id.Lit_Digits 0>})
    right: <Id.Arith_RBrace _>
  )
}('\n---', '${foo:0:1}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name foo>
    var_name: foo
    suffix_op: (suffix_op.Slice begin:{<Id.Lit_Digits 0>} length:{<Id.Lit_Digits 1>})
    right: <Id.Arith_RBrace _>
  )
}('\n---', '${foo:1+2:2+3}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name foo>
    var_name: foo
    suffix_op: 
      (suffix_op.Slice
        begin: 
          (arith_expr.Binary
            op_id: Id.Arith_Plus
            left: {<Id.Lit_Digits 1>}
            right: {<Id.Lit_Digits 2>}
          )
        length: 
          (arith_expr.Binary
            op_id: Id.Arith_Plus
            left: {<Id.Lit_Digits 2>}
            right.......
----------------------------------------------------------------------
Ran 24 tests in 0.112s

OK
: {<Id.Lit_Digits 3>}
          )
      )
    right: <Id.Arith_RBrace _>
  )
}('\n---', '${foo::1}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name foo>
    var_name: foo
    suffix_op: (suffix_op.Slice length:{<Id.Lit_Digits 1>})
    right: <Id.Arith_RBrace _>
  )
}('\n---', '${var:-default]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VTest_ColonHyphen _> arg_word:{<'default]'>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '~/git/oilshell/oil')
{<Id.Lit_TildeLike '~'> <'/git/oilshell/oil'>}('\n---', '~andy/git/oilshell/oil')
{<Id.Lit_TildeLike '~andy'> <'/git/oilshell/oil'>}('\n---', '~andy_c/git/oilshell/oil')
{<Id.Lit_TildeLike '~andy_c'> <'/git/oilshell/oil'>}('\n---', '~andy.c/git/oilshell/oil')
{<Id.Lit_TildeLike '~andy.c'> <'/git/oilshell/oil'>}('\n---', '~andy-c/git/oilshell/oil')
{<Id.Lit_TildeLike '~andy-c'> <'/git/oilshell/oil'>}('\n---', '~andy-c:git/oilshell/oil')
{<Id.Lit_TildeLike '~andy-c'> <Id.Lit_Colon ':'> <'git/oilshell/oil'>}('\n---', '${var#}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Pound '#'> arg_word:{})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var#prefix}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Pound '#'> arg_word:{<prefix>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var##}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_DPound '##'> arg_word:{})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var##prefix}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_DPound '##'> arg_word:{<prefix>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var%suffix}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_Percent '%'> arg_word:{<suffix>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${var%%suffix}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name var>
    var_name: var
    suffix_op: (suffix_op.Unary op:<Id.VOp1_DPercent '%%'> arg_word:{<suffix>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${name}')
{(${ Id.VSub_Name name)}('\n---', '${name[0]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name name>
    var_name: name
    bracket_op: (bracket_op.ArrayIndex expr:{<Id.Lit_Digits 0>})
    right: <Id.Right_DollarBrace '}'>
  )
}('\n---', '${array[@]}')
{
  (braced_var_sub
    left: <Id.Left_DollarBrace '${'>
    token: <Id.VSub_Name array>
    var_name: array
    bracket_op: (bracket_op.WholeArray op_id:Id.Lit_At)
    right: <Id.Right_DollarBrace '}'>
  )
}