catala/compiler/surface/lexer_common.ml
Louis Gesbert fea01cfe4c Add overloaded operators for the common operations
This uses the same disambiguation mechanism put in place for
structures, calling the typer on individual rules on the desugared AST
to propagate types, in order to resolve ambiguous operators like `+`
to their strongly typed counterparts (`+!`, `+.`, `+$`, `+@`, `+$`) in
the translation to scopelang.

The patch includes some normalisation of the definition of all the
operators, and classifies them based on their typing policy instead of
their arity. It also adds a little more flexibility:
- a couple new operators, like `-` on date and duration
- optional type annotation on some aggregation constructions

The `Shared_ast` lib is also lightly restructured, with the `Expr`
module split into `Type`, `Operator` and `Expr`.
2022-12-13 11:55:24 +01:00

113 lines
4.0 KiB
OCaml

(* This file is part of the Catala compiler, a specification language for tax
and social benefits computation rules. Copyright (C) 2020 Inria,
contributors: Denis Merigoux <denis.merigoux@inria.fr>, Emile Rolley
<emile.rolley@tuta.io>
Licensed under the Apache License, Version 2.0 (the "License"); you may not
use this file except in compliance with the License. You may obtain a copy of
the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations under
the License. *)
open Tokens
open Sedlexing
open Catala_utils
module R = Re.Pcre
(* Calculates the precedence according a {!val: matched_regex} of the form :
'[#]+'.
@note -2 because [LAW_HEADING] start with at least "#" and the number of '#'
remaining corresponds to the precedence. *)
let calc_precedence (matched_regex : string) : int =
String.length matched_regex - 1
(* Gets the [LAW_HEADING] token from the current {!val: lexbuf} *)
let get_law_heading (lexbuf : lexbuf) : token =
let extract_article_title =
R.regexp "([#]+)\\s*([^\\|]+)(\\|\\s*([^\\s]+)|)(\\s*(\\[archive\\])|)"
in
let rex = R.exec ~rex:extract_article_title (Utf8.lexeme lexbuf) in
let title = String.trim (R.get_substring rex 2) in
let article_id =
try Some (String.trim (R.get_substring rex 4)) with Not_found -> None
in
let is_archive = Option.is_some (Re.Group.get_opt rex 6) in
let precedence = calc_precedence (String.trim (R.get_substring rex 1)) in
LAW_HEADING (title, article_id, is_archive, precedence)
type lexing_context = Law | Code | Directive | Directive_args
(** Boolean reference, used by the lexer as the mutable state to distinguish
whether it is lexing code or law. *)
let context : lexing_context ref = ref Law
(** Mutable string reference that accumulates the string representation of the
body of code being lexed. This string representation is used in the literate
programming backends to faithfully capture the spacing pattern of the
original program *)
let code_buffer : Buffer.t = Buffer.create 4000
(** Updates {!val:code_buffer} with the current lexeme *)
let update_acc (lexbuf : lexbuf) : unit =
Buffer.add_string code_buffer (Utf8.lexeme lexbuf)
(** Error-generating helper *)
let raise_lexer_error (loc : Pos.t) (token : string) =
Errors.raise_spanned_error loc
"Parsing error after token \"%s\": what comes after is unknown" token
(** Associative list matching each punctuation string part of the Catala syntax
with its {!module: Surface.Parser} token. Same for all the input languages
(English, French, etc.) *)
let token_list_language_agnostic : (string * token) list =
[
".", DOT;
"<=", LESSER_EQUAL KPoly;
">=", GREATER_EQUAL KPoly;
">", GREATER KPoly;
"!=", NOT_EQUAL;
"=", EQUAL;
"(", LPAREN;
")", RPAREN;
"{", LBRACKET;
"}", RBRACKET;
"{", LSQUARE;
"}", RSQUARE;
"+", PLUS KPoly;
"-", MINUS KPoly;
"*", MULT KPoly;
"/", DIV KPoly;
"|", VERTICAL;
":", COLON;
";", SEMICOLON;
"--", ALT;
"++", PLUSPLUS;
]
module type LocalisedLexer = sig
val token_list : (string * Tokens.token) list
(** Same as {!val: token_list_language_agnostic}, but with tokens specialized
to a given language. *)
val lex_builtin : string -> Ast.builtin_expression option
(** Simple lexer for builtins *)
val lex_code : Sedlexing.lexbuf -> Tokens.token
(** Main lexing function used in code blocks *)
val lex_law : Sedlexing.lexbuf -> Tokens.token
(** Main lexing function used outside code blocks *)
val lexer : Sedlexing.lexbuf -> Tokens.token
(** Entry point of the lexer, distributes to {!val: lex_code} or
{!val:lex_law} depending of the current {!val:
Surface.Lexer_common.context}. *)
end