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esperbuild/espersrc/fennel-0.7.0/src/linter.fnl
| 1 | ;; An example of some possible linters using Fennel's --plugin option. |
| 2 | |
| 3 | ;; The first two linters here can only function on static module |
| 4 | ;; use. For instance, this code can be checked because they use static |
| 5 | ;; field access on a local directly bound to a require call: |
| 6 | |
| 7 | ;; (local m (require :mymodule)) |
| 8 | ;; (print m.field) ; fails if mymodule lacks a :field field |
| 9 | ;; (print (m.function 1 2 3)) ; fails unless mymodule.function takes 3 args |
| 10 | |
| 11 | ;; However, these cannot: |
| 12 | |
| 13 | ;; (local m (do (require :mymodule)) ; m is not directly bound |
| 14 | ;; (print (. m field)) ; not a static field reference |
| 15 | ;; (let [f m.function] |
| 16 | ;; (print (f 1 2 3)) ; intermediate local, not a static field call on m |
| 17 | |
| 18 | ;; Still, pretty neat, huh? |
| 19 | |
| 20 | ;; This file is provided as an example and is not part of Fennel's public API. |
| 21 | |
| 22 | (fn save-require-meta [from to scope] |
| 23 | "When destructuring, save module name if local is bound to a `require' call. |
| 24 | Doesn't do any linting on its own; just saves the data for other linters." |
| 25 | (when (and (sym? to) (not (multi-sym? to)) (list? from) |
| 26 | (sym? (. from 1)) (= :require (tostring (. from 1))) |
| 27 | (= :string (type (. from 2)))) |
| 28 | (let [meta (. scope.symmeta (tostring to))] |
| 29 | (set meta.required (tostring (. from 2)))))) |
| 30 | |
| 31 | (fn check-module-fields [symbol scope] |
| 32 | "When referring to a field in a local that's a module, make sure it exists." |
| 33 | (let [[module-local field] (or (multi-sym? symbol) []) |
| 34 | module-name (-?> scope.symmeta (. (tostring f-local)) (. :required)) |
| 35 | module (and module-name (require module-name))] |
| 36 | (assert-compile (or (= module nil) (not= (. module field) nil)) |
| 37 | (string.format "Missing field %s in module %s" |
| 38 | (or field :?) (or module-name :?)) symbol))) |
| 39 | |
| 40 | (fn arity-check? [module] (-?> module getmetatable (. :arity-check?))) |
| 41 | |
| 42 | (fn arity-check-call [[f & args] scope] |
| 43 | "Perform static arity checks on static function calls in a module." |
| 44 | (let [arity (# args) |
| 45 | last-arg (. args arity) |
| 46 | [f-local field] (or (multi-sym? f) []) |
| 47 | module-name (-?> scope.symmeta (. (tostring f-local)) (. :required)) |
| 48 | module (and module-name (require module-name))] |
| 49 | (when (and (arity-check? module) debug debug.getinfo |
| 50 | (not (varg? last-arg)) (not (list? last-arg))) |
| 51 | (assert-compile (= (type (. module field)) :function) |
| 52 | (string.format "Missing function %s in module %s" |
| 53 | (or field :?) module-name) f) |
| 54 | (match (debug.getinfo (. module field)) |
| 55 | {: nparams :what "Lua" :isvararg true} |
| 56 | (assert-compile (<= nparams (# args)) |
| 57 | (: "Called %s.%s with %s arguments, expected %s+" |
| 58 | :format f-local field arity nparams) f) |
| 59 | {: nparams :what "Lua" :isvararg false} |
| 60 | (assert-compile (= nparams (# args)) |
| 61 | (: "Called %s.%s with %s arguments, expected %s" |
| 62 | :format f-local field arity nparams) f))))) |
| 63 | |
| 64 | (fn check-unused [ast scope] |
| 65 | (each [symname (pairs scope.symmeta)] |
| 66 | (assert-compile (or (. scope.symmeta symname :used) (symname:find "^_")) |
| 67 | (string.format "unused local %s" (or symname :?)) ast))) |
| 68 | |
| 69 | {:destructure save-require-meta |
| 70 | :symbol-to-expression check-module-fields |
| 71 | :call arity-check-call |
| 72 | ;; Note that this will only check unused args inside functions and let blocks, |
| 73 | ;; not top-level locals of a chunk. |
| 74 | :fn check-unused |
| 75 | :do check-unused} |