refactor(library/init/lean): share error function between expander and elaborator

library/init/lean/elaborator.lean

@@ -19,11 +19,13 @@ open parser.command
 open parser.command.notation_spec
 open expander
 
-structure elaborator_config :=
-(filename : string)
+structure elaborator_config extends frontend_config :=
 (local_notations : list notation_macro := [])
 (initial_parser_cfg : module_parser_config)
 
+instance elaborator_config_coe_frontend_config : has_coe elaborator_config frontend_config :=
+⟨elaborator_config.to_frontend_config⟩
+
 structure elaborator_state :=
 -- TODO(Sebastian): retrieve from environment
 (reserved_notations : list reserve_notation.view := [])
@@ -61,11 +63,6 @@ instance elaborator_m_coe_coelaborator_m {α : Type} : has_coe (elaborator_m α)
 instance elaborator_coe_coelaborator : has_coe elaborator coelaborator :=
 ⟨λ x, do stx ← current_command, x stx⟩
 
-def error {α : Type} (context : syntax) (text : string) : elaborator_m α :=
-do cfg ← read,
-   -- TODO(Sebastian): convert position
-   throw {filename := cfg.filename, pos := /-context.get_pos.get_or_else-/ ⟨1,0⟩, text := text}
-
 local attribute [instance] name.has_lt_quick
 
 def mangle_ident (id : syntax_ident) : name :=

library/init/lean/expander.lean

@@ -19,12 +19,15 @@ open parser.combinators
 open parser.term
 open parser.command
 
-structure transformer_config :=
-(filename : string)
+structure transformer_config extends frontend_config
+-- TODO(Sebastian): the recursion point for `local_expand` probably needs to be stored here
+
+instance transformer_config_coe_frontend_config : has_coe transformer_config frontend_config :=
+⟨transformer_config.to_frontend_config⟩
 
 -- TODO(Sebastian): recursive expansion
 @[derive monad monad_reader monad_except]
-def transform_m := reader_t transformer_config $ except_t message id
+def transform_m := reader_t frontend_config $ except_t message id
 abbreviation transformer := syntax → transform_m (option syntax)
 
 /-- We allow macros to refuse expansion. This means that nodes can decide whether to act as macros
@@ -33,12 +36,12 @@ abbreviation transformer := syntax → transform_m (option syntax)
 def no_expansion : transform_m (option syntax) :=
 pure none
 
-def error {m : Type → Type} {ρ : Type} [monad m] [monad_reader ρ m] [has_lift_t ρ transformer_config]
+def error {m : Type → Type} {ρ : Type} [monad m] [monad_reader ρ m] [has_lift_t ρ frontend_config]
   [monad_except message m] {α : Type}
   (context : syntax) (text : string) : m α :=
 do cfg ← read,
    -- TODO(Sebastian): convert position
-   throw {filename := transformer_config.filename ↑cfg, pos := /-context.get_pos.get_or_else-/ ⟨1,0⟩, text := text}
+   throw {filename := frontend_config.filename ↑cfg, pos := /-context.get_pos.get_or_else-/ ⟨1,0⟩, text := text}
 
 /-- Coercion useful for introducing macro-local variables. Use `glob_id` to refer to global bindings instead. -/
 instance coe_name_ident : has_coe name syntax_ident :=

library/init/lean/parser/basic.lean

@@ -57,11 +57,16 @@ structure parser_cache :=
 -- for profiling
 (hit miss : nat := 0)
 
-/- Remark: if we have a node in the trie with `some token_config`, the string induced by the path is equal to the `token_config.prefix`. -/
-structure parser_config :=
-(tokens : trie token_config)
+structure frontend_config :=
 (filename : string)
 
+/- Remark: if we have a node in the trie with `some token_config`, the string induced by the path is equal to the `token_config.prefix`. -/
+structure parser_config extends frontend_config :=
+(tokens : trie token_config)
+
+instance parser_config_coe : has_coe parser_config frontend_config :=
+⟨parser_config.to_frontend_config⟩
+
 @[derive monad alternative monad_parsec monad_except]
 def parser_core_t (m : Type → Type) [monad m] :=
 parsec_t syntax $ state_t parser_cache $ m
@@ -115,12 +120,12 @@ instance has_view.default (r : ρ) : inhabited (parser.has_view syntax r) :=
 
 class has_view_default (r : ρ) (α : out_param Type) [has_view α r] (default : α) := mk {}
 
-def message_of_parsec_message {μ : Type} (cfg : parser_config) (msg : parsec.message μ) : message :=
+def message_of_parsec_message {μ : Type} (cfg : frontend_config) (msg : parsec.message μ) : message :=
 -- FIXME: translate position
 {filename := cfg.filename, pos := ⟨0, 0⟩, text := to_string msg}
 
 /-- Run parser stack, returning a partial syntax tree in case of a fatal error -/
-protected def run {m : Type → Type} {α ρ : Type} [monad m] [has_coe_t ρ parser_config] (cfg : ρ) (s : string) (r : state_t parser_state (parser_t ρ m) α) :
+protected def run {m : Type → Type} {α ρ : Type} [monad m] [has_coe_t ρ frontend_config] (cfg : ρ) (s : string) (r : state_t parser_state (parser_t ρ m) α) :
 m (sum α syntax × message_log) :=
 do (r, _) ← (((r.run {messages:=message_log.empty}).run cfg).parse s).run {},
 pure $ match r with
@@ -133,7 +138,7 @@ open parser.has_view
 variables {α : Type} {m : Type → Type}
 local notation `parser` := m syntax
 
-def log_message {μ : Type} [monad m] [monad_reader ρ m] [has_lift_t ρ parser_config] [monad_state parser_state m]
+def log_message {μ : Type} [monad m] [monad_reader ρ m] [has_lift_t ρ frontend_config] [monad_state parser_state m]
   (msg : parsec.message μ) : m unit :=
 do cfg ← read,
    modify (λ st, {st with messages := st.messages.add (message_of_parsec_message ↑cfg msg)})