56 lines
1.9 KiB
OCaml
56 lines
1.9 KiB
OCaml
open Ppxlib
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let log_expander ~ctxt (e : expression) (l : (arg_label * expression) list) : expression =
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let loc = Expansion_context.Extension.extension_point_loc ctxt in
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let is_exn = begin match e.pexp_desc with
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| Pexp_ident { txt = Lident "trace"; _ }
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| Pexp_ident { txt = Lident "debug"; _ }
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| Pexp_ident { txt = Lident "info"; _ }
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| Pexp_ident { txt = Lident "warn"; _ }
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| Pexp_ident { txt = Lident "error"; _ } -> false
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| Pexp_ident { txt = Lident "exn"; _ } -> true
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| _ ->
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raise (Location.Error (Location.Error.make ~loc ~sub:[]
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"log type must be one of: trace, debug, info, warn, error, exn"))
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end in
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let open (val Ast_builder.make loc) in
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if is_exn then
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match l with
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| [] ->
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raise (Location.Error (Location.Error.make ~loc ~sub:[]
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"must provide exn value"))
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| (_, v)::l ->
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let application =
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eapply (pexp_ident { txt = Lident "m"; loc}) (List.map snd l) in
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[%expr [%e e] [%e v] (Printexc.get_raw_backtrace ()) ~__POS__ ~__FUNCTION__
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(fun m -> [%e application])]
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else
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let application =
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eapply (pexp_ident { txt = Lident "m"; loc}) (List.map snd l) in
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[%expr [%e e] ~__POS__ ~__FUNCTION__ (fun m -> [%e application])]
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let log_extension =
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let pattern =
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let open Ast_pattern in
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pstr (pstr_eval (pexp_apply __ __) nil ^:: nil)
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in
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Context_free.Rule.extension
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(Extension.V3.declare "xlog" Expression pattern log_expander)
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let import_expander ~ctxt _e : structure_item =
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let loc = Expansion_context.Extension.extension_point_loc ctxt in
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[%stri include (val Xlog.logs __FUNCTION__)]
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let import_extension =
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let pattern =
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let open Ast_pattern in
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__
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in
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Context_free.Rule.extension
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(Extension.V3.declare "xlog_import" Structure_item pattern import_expander)
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let () =
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Driver.register_transformation
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~rules:[ log_extension; import_extension ]
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"xlog.ppx"
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