Supported indexable lvalues

• Direct/indirect field name like $x or $["x"]
• Direct/indirect oosvar like @x or @["x"]
• Local variable like x
• Full srec $*
• Full oosvar @*

Supported indexing

Each level by int or string:

• $x[1] or $x["a"]
• @x[1] or @x["a"]
• x[1] or x["a"]
• $*[1] or $*["a"]
• @*[1] (not supported) or @*["a"]

Multiple levels:

• Each can be further indexed, e.g. $x[1]["a"][3]

Auto-deepen:

• x[1][2][3] = 4 should auto-deepen
• x["a"]["b"]["c"] = 4 should auto-deepen
  • Create new maps at each level if necessary, unless they're already something else -- like x["a"] is already int/array/etc.

Indexed types

• $x is a Mlrval
• @x is a Mlrval
• x is a `Mlrval
• $* is a Mlrmap
• @* is a Mlrmap

Implementation

• *Mlrval needs a PutIndexed which takes indices []*Mlrval and rvalue *Mlrval.
• *Mlrmap needs a PutIndexed which takes indices []*Mlrval and rvalue *Mlrval.