diff --git a/compiler/scalc/to_r.ml b/compiler/scalc/to_r.ml
index 9c16fea2..9204d7cd 100644
--- a/compiler/scalc/to_r.ml
+++ b/compiler/scalc/to_r.ml
@@ -32,12 +32,20 @@ let format_lit (fmt : Format.formatter) (l : lit Mark.pos) : unit =
     else
       Format.fprintf fmt "catala_integer_from_string(\"%s\")"
         (Runtime.integer_to_string i)
-  | LUnit -> Format.pp_print_string fmt "catala_unit(v=0)"
+  | LUnit -> Format.pp_print_string fmt "new(\"catala_unit\",v=0)"
   | LRat i ->
-    Format.fprintf fmt "catala_decimal_from_string(\"%a\")" Print.lit (LRat i)
+    Format.fprintf fmt "catala_decimal_from_fraction(%s,%s)"
+      (if Z.fits_nativeint (Q.num i) then Z.to_string (Q.num i)
+      else "\"" ^ Z.to_string (Q.num i) ^ "\"")
+      (if Z.fits_nativeint (Q.den i) then Z.to_string (Q.den i)
+      else "\"" ^ Z.to_string (Q.den i) ^ "\"")
   | LMoney e ->
-    Format.fprintf fmt "catala_money_from_cents(\"%s\")"
-      (Runtime.integer_to_string (Runtime.money_to_cents e))
+    if Z.fits_nativeint e then
+      Format.fprintf fmt "catala_money_from_cents(%s)"
+        (Runtime.integer_to_string (Runtime.money_to_cents e))
+    else
+      Format.fprintf fmt "catala_money_from_cents(\"%s\")"
+        (Runtime.integer_to_string (Runtime.money_to_cents e))
   | LDate d ->
     Format.fprintf fmt "catala_date_from_ymd(%d,%d,%d)"
       (Runtime.integer_to_int (Runtime.year_of_date d))
diff --git a/runtimes/r/NAMESPACE b/runtimes/r/NAMESPACE
index 6290a784..0e0baee4 100644
--- a/runtimes/r/NAMESPACE
+++ b/runtimes/r/NAMESPACE
@@ -2,33 +2,29 @@
 
 export(catala_assertion_failure)
 export(catala_conflict_error)
-export(catala_date)
 export(catala_date_first_day_of_month)
 export(catala_date_from_ymd)
 export(catala_date_last_day_of_month)
 export(catala_date_to_string)
 export(catala_day_of_month_of_date)
-export(catala_decimal)
+export(catala_decimal_from_fraction)
 export(catala_decimal_from_integer)
 export(catala_decimal_from_money)
 export(catala_decimal_from_numeric)
-export(catala_decimal_from_string)
 export(catala_decimal_round)
 export(catala_decimal_to_numeric)
-export(catala_duration)
 export(catala_duration_from_ymd)
 export(catala_duration_to_ymd)
 export(catala_empty_error)
 export(catala_handle_default)
-export(catala_integer)
 export(catala_integer_from_numeric)
 export(catala_integer_from_string)
 export(catala_integer_to_numeric)
 export(catala_list_filter)
+export(catala_list_fold_left)
 export(catala_list_length)
 export(catala_list_map)
 export(catala_list_reduce)
-export(catala_money)
 export(catala_money_from_cents)
 export(catala_money_from_decimal)
 export(catala_money_from_units)
@@ -37,9 +33,7 @@ export(catala_money_to_numeric)
 export(catala_money_to_string)
 export(catala_month_number_of_date)
 export(catala_no_value_provided_error)
-export(catala_position)
 export(catala_position_to_string)
-export(catala_unit)
 export(catala_year_of_date)
 export(dead_value)
 exportClasses(catala_date)
diff --git a/runtimes/r/R/runtime.R b/runtimes/r/R/runtime.R
index ec872427..fb7e305d 100644
--- a/runtimes/r/R/runtime.R
+++ b/runtimes/r/R/runtime.R
@@ -7,7 +7,7 @@
 #' @export
 setClass(
   "catala_integer",
-  representation(v = "bigz"),
+  representation(v = "bigz")
 )
 #' @export
 setMethod("Arith", "catala_integer", function(e1, e2) {
@@ -16,7 +16,7 @@ setMethod("Arith", "catala_integer", function(e1, e2) {
 })
 #' @export
 setMethod("-", c("catala_integer", "missing"), function(e1) {
-  catala_integer(v = -e1@v)
+  new("catala_integer", v = -e1@v)
 })
 #' @export
 setMethod("Compare", "catala_integer", function(e1, e2) {
@@ -28,7 +28,7 @@ setMethod("Compare", "catala_integer", function(e1, e2) {
 #' @export
 setClass(
   "catala_decimal",
-  representation(v = "bigq"),
+  representation(v = "bigq")
 )
 #' @export
 setMethod("Arith", "catala_decimal", function(e1, e2) {
@@ -37,7 +37,7 @@ setMethod("Arith", "catala_decimal", function(e1, e2) {
 })
 #' @export
 setMethod("-", c("catala_decimal", "missing"), function(e1) {
-  catala_decimal(v = -e1@v)
+  new("catala_decimal", v = -e1@v)
 })
 #' @export
 setMethod("Compare", "catala_decimal", function(e1, e2) {
@@ -49,27 +49,27 @@ setMethod("Compare", "catala_decimal", function(e1, e2) {
 #' @export
 setClass(
   "catala_money",
-  representation(v = "bigz"),
+  representation(v = "bigz")
 )
 #' @export
 setMethod("+", c("catala_money", "catala_money"), function(e1, e2) {
-  catala_money(v = e1@v + e2@v)
+  new("catala_money", v = e1@v + e2@v)
 })
 #' @export
 setMethod("-", c("catala_money", "catala_money"), function(e1, e2) {
-  catala_money(v = e1@v - e2@v)
+  new("catala_money", v = e1@v - e2@v)
 })
 #' @export
 setMethod("-", c("catala_money", "missing"), function(e1) {
-  catala_money(v = -e1@v)
+  new("catala_money", v = -e1@v)
 })
 #' @export
 setMethod("*", c("catala_money", "catala_decimal"), function(e1, e2) {
-  catala_money(v = as.bigz(as.bigq(e1@v) * e2@v))
+  new("catala_money", v = as.bigz(as.bigq(e1@v) * e2@v))
 })
 #' @export
 setMethod("/", c("catala_money", "catala_money"), function(e1, e2) {
-  catala_decimal(v = as.bigq(e1@v / e2@v))
+  new("catala_decimal", v = as.bigq(e1@v / e2@v))
 })
 #' @export
 setMethod("Compare", "catala_money", function(e1, e2) {
@@ -79,25 +79,25 @@ setMethod("Compare", "catala_money", function(e1, e2) {
 ################ Duration #################
 
 #' @export
-suppressWarnings(setClass(
+setClass(
   "catala_duration",
   representation(v = "Period")
-))
+)
 #' @export
 setMethod("+", c("catala_duration", "catala_duration"), function(e1, e2) {
-  catala_duration(v = e1@v + e2@v)
+  new("catala_duration", v = e1@v + e2@v)
 })
 #' @export
 setMethod("-", c("catala_duration", "catala_duration"), function(e1, e2) {
-  catala_duration(v = e1@v - e2@v)
+  new("catala_duration", v = e1@v - e2@v)
 })
 #' @export
 setMethod("-", c("catala_duration", "missing"), function(e1) {
-  catala_duration(v = -e1@v)
+  new("catala_duration", v = -e1@v)
 })
 #' @export
 setMethod("/", c("catala_duration", "catala_duration"), function(e1, e2) {
-  catala_duration(v = e1@v / e2@v)
+  new("catala_duration", v = e1@v / e2@v)
 })
 #' @export
 setMethod("Compare", "catala_duration", function(e1, e2) {
@@ -113,15 +113,15 @@ setMethod("Compare", "catala_duration", function(e1, e2) {
 #' @export
 setClass(
   "catala_date",
-  representation(v = "Date"),
+  representation(v = "Date")
 )
 #' @export
 setMethod("+", c("catala_date", "catala_duration"), function(e1, e2) {
-  catala_date(v = e1@v + e2@v)
+  new("catala_date", v = e1@v + e2@v)
 })
 #' @export
 setMethod("-", c("catala_date", "catala_date"), function(e1, e2) {
-  catala_date(v = e1@v - e2@v)
+  new("catala_date", v = e1@v - e2@v)
 })
 #' @export
 setMethod("Compare", "catala_date", function(e1, e2) {
@@ -131,7 +131,7 @@ setMethod("Compare", "catala_date", function(e1, e2) {
 ################ Unit #################
 
 #' @export
-catala_unit <- setClass("catala_unit", representation(v = "numeric"))
+setClass("catala_unit", representation(v = "numeric"))
 
 ################ Constructors and conversions #################
 
@@ -139,11 +139,11 @@ catala_unit <- setClass("catala_unit", representation(v = "numeric"))
 
 #' @export
 catala_money_from_units <- function(x) {
-  catala_money(v = as.bigz(x) * as.bigz(100))
+  new("catala_money", v = as.bigz(x) * as.bigz(100))
 }
 #' @export
 catala_money_from_cents <- function(x) {
-  catala_money(v = as.bigz(x))
+  new("catala_money", v = as.bigz(x))
 }
 #' @export
 catala_money_from_decimal <- function(d) {
@@ -151,9 +151,9 @@ catala_money_from_decimal <- function(d) {
   unit_part_num_cents_z <- as.bigz(num_cents_q)
   remainder_q <- num_cents_q - as.bigq(unit_part_num_cents_z)
   if (remainder_q < as.bigq(0.5)) {
-    catala_money(v = as.bigz(sign(d@v)) * unit_part_num_cents_z)
+    new("catala_money", v = as.bigz(sign(d@v)) * unit_part_num_cents_z)
   } else {
-    catala_money(v = as.bigz(sign(d@v)) * (unit_part_num_cents_z + as.bigz(1)))
+    new("catala_money", v = as.bigz(sign(d@v)) * (unit_part_num_cents_z + as.bigz(1)))
   }
 }
 #' @export
@@ -169,9 +169,9 @@ catala_money_round <- function(m) {
   q <- abs(m@v) %/% as.bigz(100)
   r <- abs(m@v) %% as.bigz(100)
   if (abs(r) < 50) {
-    catala_money(v = sign(m@v) * q * as.bigz(100))
+    new("catala_money", v = sign(m@v) * q * as.bigz(100))
   } else {
-    catala_money(v = sign(m@v) * (q + 1) * as.bigz(100))
+    new("catala_money", v = sign(m@v) * (q + 1) * as.bigz(100))
   }
 }
 
@@ -180,15 +180,15 @@ catala_money_round <- function(m) {
 
 #' @export
 catala_decimal_from_numeric <- function(x) {
-  catala_decimal(v = as.bigq(x))
+  new("catala_decimal", v = as.bigq(x))
 }
 #' @export
-catala_decimal_from_string <- function(x) {
-  catala_decimal(v = as.bigq(x))
+catala_decimal_from_fraction <- function(x, y) {
+  new("catala_decimal", v = as.bigq(n = x, d = y))
 }
 #' @export
 catala_decimal_from_integer <- function(x) {
-  catala_decimal(v = as.bigq(x@v))
+  new("catala_decimal", v = as.bigq(x@v))
 }
 #' @export
 catala_decimal_to_numeric <- function(x) {
@@ -199,25 +199,25 @@ catala_decimal_round <- function(d) {
   q <- abs(as.bigq(as.bigz(d@v)))
   r <- abs(d@v) - as.bigq(q)
   if (r < as.bigq(0.5)) {
-    catala_decimal(v = sign(d@v) * q)
+    new("catala_decimal", v = sign(d@v) * q)
   } else {
-    catala_decimal(v = sign(d@v) * (q + as.bigq(1)))
+    new("catala_decimal", v = sign(d@v) * (q + as.bigq(1)))
   }
 }
 #' @export
 catala_decimal_from_money <- function(m) {
-  catala_decimal(v = as.bigq(as.bigq(m@v) / as.bigq(100)))
+  new("catala_decimal", v = as.bigq(as.bigq(m@v) / as.bigq(100)))
 }
 
 # Integers
 
 #' @export
 catala_integer_from_numeric <- function(x) {
-  catala_integer(v = as.bigz(x))
+  new("catala_integer", v = as.bigz(x))
 }
 #' @export
 catala_integer_from_string <- function(x) {
-  catala_integer(v = as.bigz(x))
+  new("catala_integer", v = as.bigz(x))
 }
 #' @export
 catala_integer_to_numeric <- function(x) {
@@ -228,7 +228,7 @@ catala_integer_to_numeric <- function(x) {
 
 #' @export
 catala_date_from_ymd <- function(y, m, d) {
-  catala_date(v = make_date(year = y, month = m, day = d))
+  new("catala_date", v = make_date(year = y, month = m, day = d))
 }
 #' @export
 catala_day_of_month_of_date <- function(d) {
@@ -248,11 +248,11 @@ catala_date_to_string <- function(d) {
 }
 #' @export
 catala_date_first_day_of_month <- function(d) {
-  catala_date(v = make_date(year = year(d@v), month = month(d@v), day = 1))
+  new("catala_date", v = make_date(year = year(d@v), month = month(d@v), day = 1))
 }
 #' @export
 catala_date_last_day_of_month <- function(d) {
-  catala_date(v = make_date(
+  new("catala_date", v = make_date(
     year = year(d@v),
     month = month(d@v),
     day = days_in_month(d@v)
@@ -263,7 +263,7 @@ catala_date_last_day_of_month <- function(d) {
 
 #' @export
 catala_duration_from_ymd <- function(y, m, d) {
-  catala_duration(v = years(y) + months(m) + days(d))
+  new("catala_duration", v = years(y) + months(m) + days(d))
 }
 #' @export
 catala_duration_to_ymd <- function(d) {
@@ -272,6 +272,7 @@ catala_duration_to_ymd <- function(d) {
 
 # List
 
+#' @export
 catala_list_fold_left <- function(f, init, l) {
   Reduce(f, l, init)
 }
@@ -362,7 +363,7 @@ catala_assertion_failure <- function(pos) {
 catala_handle_default <- function(pos, exceptions, just, cons) {
   acc <- Reduce(function(acc, exception) {
     new_val <- tryCatch(
-      exception(catala_unit(v = 0)),
+      exception(new("catala_unit", v = 0)),
       catala_empty_error = function(e) {
         NULL
       }
@@ -378,8 +379,8 @@ catala_handle_default <- function(pos, exceptions, just, cons) {
     }
   }, exceptions, NULL)
   if (is.null(acc)) {
-    if (just(catala_unit(v = 0))) {
-      cons(catala_unit(v = 0))
+    if (just(new("catala_unit", v = 0))) {
+      cons(new("catala_unit", v = 0))
     } else {
       stop(catala_empty_error())
     }
@@ -392,5 +393,6 @@ catala_handle_default <- function(pos, exceptions, just, cons) {
 # it to accept dead code. Indeed, when raising an exception during a variable
 # definition, R could complains that the later dead code will not know what
 # this variable was. So we give this variable a dead value.
+
 #' @export
 dead_value <- 0