Module Mlang.Mast

Abstract Syntax Tree

Names

type application = string

Applications are rule annotations. The 3 main DGFiP applications seem to be:

  • batch: deprecated, used to compute the income tax but not anymore;
  • bareme: seems to compute the income tax;
  • iliad: usage unkown, much bigger than bareme.
type chaining = string

"enchaineur" in the M source code, utility unknown

type variable_name = string

Variables are just strings

type func_name = string

Func names are just string for the moment

type variable_generic_name = {
base : string;
parameters : char list;
}

For generic variables, we record the list of their lowercase parameters

type error_name = string

Ununsed for now

Literals

type variable =
| Normal of variable_name
| Generic of variable_generic_name

A variable is either generic (with loop parameters) or normal

val get_normal_var : variable -> variable_name
type table_size =
| LiteralSize of int
| SymbolSize of string
val get_table_size : table_size -> int
val get_table_size_opt : (table_size * 'a) option -> (int * 'a) option

Expressions

type var_category_id = string Pos.marked list Pos.marked
type set_value = variable Com.set_value
type expression = variable Com.expression
type m_expression = expression Pos.marked

Toplevel clauses

Rules

type instruction = (variable, error_name) Com.instruction
type m_instruction = instruction Pos.marked
type rule = {
rule_number : int Pos.marked;
rule_tag_names : string Pos.marked list Pos.marked;
rule_apps : application Pos.marked Mlang.StrMap.t;
rule_chainings : chaining Pos.marked Mlang.StrMap.t;
rule_tmp_vars : (string Pos.marked * table_size Pos.marked option) Mlang.StrMap.t;
rule_formulaes : instruction Pos.marked list;

A rule can contain many variable definitions

}
type target = {
target_name : string Pos.marked;
target_file : string option;
target_apps : application Pos.marked Mlang.StrMap.t;
target_args : string Pos.marked list;
target_result : string Pos.marked option;
target_tmp_vars : (string Pos.marked * table_size Pos.marked option) Mlang.StrMap.t;
target_nb_tmps : int;
target_sz_tmps : int;
target_nb_refs : int;
target_prog : instruction Pos.marked list;
}
type 'a domain_decl = {
dom_names : string Pos.marked list Pos.marked list;
dom_parents : string Pos.marked list Pos.marked list;
dom_by_default : bool;
dom_data : 'a;
}
type rule_domain_data = {
rdom_computable : bool;
}
type rule_domain_decl = rule_domain_data domain_decl

Variable declaration

Input variables

type variable_attribute = string Pos.marked * int Pos.marked
type input_variable = {
input_name : variable_name Pos.marked;
input_category : string Pos.marked list;
input_attributes : variable_attribute list;
input_alias : variable_name Pos.marked;

Unused for now

input_is_givenback : bool;
input_description : string Pos.marked;
input_typ : Com.value_typ Pos.marked option;
}
type computed_variable = {
comp_name : variable_name Pos.marked;
comp_table : table_size Pos.marked option;

size of the table, None for non-table variables

comp_attributes : variable_attribute list;
comp_category : string Pos.marked list;
comp_typ : Com.value_typ Pos.marked option;
comp_is_givenback : bool;
comp_description : string Pos.marked;
}
type variable_decl =
| ComputedVar of computed_variable Pos.marked
| ConstVar of variable_name Pos.marked * variable Com.atom Pos.marked

The literal is the constant value

| InputVar of input_variable Pos.marked
type var_type =
| Input
| Computed
type var_category_decl = {
var_type : var_type;
var_category : string Pos.marked list;
var_attributes : string Pos.marked list;
}
val input_category : string
val computed_category : string
val base_category : string
val givenback_category : string

Verification clauses

type verification_condition = {
verif_cond_expr : expression Pos.marked;
verif_cond_error : error_name Pos.marked * variable_name Pos.marked option;

A verification condition error can ba associated to a variable

}
type verification = {
verif_number : int Pos.marked;
verif_tag_names : string Pos.marked list Pos.marked;
verif_apps : application Pos.marked Mlang.StrMap.t;

Verification conditions are application-specific

verif_conditions : verification_condition Pos.marked list;
}
type verif_domain_data = {
vdom_auth : var_category_id list;
vdom_verifiable : bool;
}
type verif_domain_decl = verif_domain_data domain_decl
type error_ = {
error_name : error_name Pos.marked;
error_typ : Com.Error.typ Pos.marked;
error_descr : string Pos.marked list;
}

M programs

type source_file_item =
| Application of application Pos.marked

Declares an application

| Chaining of chaining Pos.marked * application Pos.marked list
| VariableDecl of variable_decl
| Function of target
| Rule of rule
| Target of target
| Verification of verification
| Error of error_

Declares an error

| Output of variable_name Pos.marked

Declares an output variable

| Func

Declares a function, unused

| VarCatDecl of var_category_decl Pos.marked
| RuleDomDecl of rule_domain_decl
| VerifDomDecl of verif_domain_decl
type source_file = source_file_item Pos.marked list
type program = source_file list

Helper functions

val get_variable_name : variable -> string