Top-level bindings in ghci
ghci now supports most of the declarations. However, it doesn't support the most basic and common type of declaraion — pattern and function bindings!
E.g.
```
Prelude> a = 1
<interactive>:2:3: parse error on input `='
```
I realise that, if implemented, they would have somewhat different semantics than in Haskell modules — e.g. with respect to recursion.
But even if they behaved in the same way as top-level monadic let-bindings, they would still be very useful for two reasons:
1. If you're doing quick experiments in ghci, "let a=1" is more than twice as long as "a=1", and that makes a difference.
1. Novices are often confused when they are told that they have to use one syntax for definitions in modules and another in ghci.
<details><summary>Trac metadata</summary>
| Trac field | Value |
| ---------------------- | -------------- |
| Version | 7.6.1 |
| Type | FeatureRequest |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | GHCi |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture | |
</details>
<!-- {"blocked_by":[],"summary":"Top-level bindings in ghci","status":"New","operating_system":"","component":"GHCi","related":[],"milestone":"","resolution":"Unresolved","owner":{"tag":"Unowned"},"version":"7.6.1","keywords":[],"differentials":[],"test_case":"","architecture":"","cc":[""],"type":"FeatureRequest","description":"ghci now supports most of the declarations. However, it doesn't support the most basic and common type of declaraion — pattern and function bindings!\r\n\r\nE.g.\r\n\r\n{{{\r\nPrelude> a = 1\r\n\r\n<interactive>:2:3: parse error on input `='\r\n}}}\r\n\r\nI realise that, if implemented, they would have somewhat different semantics than in Haskell modules — e.g. with respect to recursion.\r\n\r\nBut even if they behaved in the same way as top-level monadic let-bindings, they would still be very useful for two reasons:\r\n\r\n1. If you're doing quick experiments in ghci, \"let a=1\" is more than twice as long as \"a=1\", and that makes a difference.\r\n\r\n2. Novices are often confused when they are told that they have to use one syntax for definitions in modules and another in ghci.\r\n","type_of_failure":"OtherFailure","blocking":[]} -->
issue