v3 Parsing: calls, indexing, literals

Expression architecture

• Expression starts at equality and descends through comparison -> term -> factor -> unary -> postfix.
• This keeps precedence simple and predictable.

Postfix chaining

postfix -> primary (call | index)*

• left-to-right chaining
• each () becomes ExprCall
• each [] becomes ExprIndex

Function declarations as statements

• fn can appear in block contexts.
• nested function parsing is just recursive parse of nested statements.

Literal parsing

• array and map are primaries.
• empty literals are legal: [], {}.
• map requires colon between key and value.

L-value checks

• assignments use parse-time target validation:
  • allowed: identifier or index expression
  • rejected: call/member/complex ops on LHS

Practice focus

• nested call + index chains
• map delimiter errors
• block/literal boundary understanding
• return with and without expression