Attempt to index a nil value

$ cat main.djot
{.foo'bar}
::: 
:::

$ lua ./bin/main.lua main.djot
lua: ./djot/ast.lua:516: attempt to index a nil value (field 'c')
stack traceback:
    ./djot/ast.lua:516: in local 'get_node'
    ./djot/ast.lua:704: in function 'djot.ast.to_ast'
    ./djot.lua:53: in method 'build_ast'
    ./bin/main.lua:97: in main chunk
    [C]: in ?

jgm / djot

Attempt to index a nil value #96