Common Errors and Solutions

This page lists frequent issues seen in Medi code and how to resolve them, with examples of the annotated diagnostics you will see.

Using '=' instead of '=='

• Symptom: assignment operator used where a comparison is intended.
• Solution: use == for equality comparison; keep = for assignment.

Example diagnostic:

error: Unexpected token: Equal
 --> line N, col M
  |
 N | if x = 3 { ... }
  |      ^  help: If you meant to compare two values, use '=='

Unmatched brackets

• Symptom: ), ], or } appears without a matching opening bracket.
• Solution: add the corresponding opening bracket earlier in the line/block.

error: Unexpected token: RightBracket
 --> line N, col M
  |
 N | list]
  |     ^  help: Did you forget a matching '[' earlier?

Stray or unrecognized text

• Symptom: Lexer error token appears (e.g., invalid symbol or garbled text).
• Solution: remove the text or replace it with a valid keyword/symbol.

error: Unrecognized token: '??='
 --> line N, col M
  |
 N | a ??= b
  |   ~~  help: This text is not valid Medi syntax. Remove it or replace with a valid symbol/keyword.

Misusing clinical operators (e.g., 'per', 'of')

• Symptom: Operator is in the wrong context or missing units.
• Solution: ensure expressions follow domain usage, e.g., mg per kg, 2 of doses.

warning: Value did not meet expected form
 --> line N, col M
  |
 N | dose per
  |      ^  help: 'per' expresses rates (e.g., 'mg per kg'). Ensure units are valid

Incomplete input

• Symptom: File ends while a statement/block is unfinished.
• Solution: complete the statement or close the block.

error: Incomplete input
 --> line 1, col 1
  |
  |  help: The parser expected more input. Did the file end unexpectedly?

Tips

• Caret (^) highlights single-character issues; tildes (~) highlight multi-character spans.
• Non-fatal parse errors surfaced during recovery are shown as warnings.
• Most diagnostics include a short help: hint with a suggested fix.