catala/doc/syntax/syntax_en.catala_en

Checking that all examples in the cheat-sheet are correct.

This file should match syntax_en.tex as closely as possible.
It is also useful for checking syntax highlighting.

# Literate programming

(we don't go to the full extent of creating dummy modules just to test these 3
cases)

```
# > Module ModuleBar
# > Using ModuleFoo
# > Include: foo.catala_en
```


# Litterals and types

```catala
declaration x content boolean equals true
declaration x content boolean equals false
declaration x content integer equals 65536
declaration x content decimal equals 65536.262144
declaration x content decimal equals 37%
declaration x content money equals $1,234,567.89
declaration x content date equals |2024-04-01|
declaration x content duration equals 254 day + 4 month + 1 year
declaration x content list of integer equals [ 12; 24; 36 ]
declaration x content (date,money,decimal) equals (|2024-04-01|, $30, 1%)
declaration scope S:
  output f content decimal depends on
    x content money,
    y content decimal
scope S:
  definition f of x, y equals x * y / $12.0

declaration x content Struct1 equals Struct1 { -- fld1: 9 -- fld2: 7% }
declaration x content Enum1 equals Case1 content 12
declaration x content Enum1 equals Case2
```

# Operators and built-ins

```catala
declaration x content integer equals
  let x equals (
    not a,        a and b,
    a or b,       # "or otherwise"
    a xor b       # exclusive or
  ) in
  let x equals (
    - a,          a + b,        a - b,
    a * b,        a / b
  ) in
  let x equals (
    a = b,        a < b,        a <= b,
    a != b,       a > b,        a >= b
  ) in
  let x equals (
    decimal of 44,
    money of 23.15
  ) in
  let x equals (
    round of $9.99
  ) in
  let x equals (
    get_month of |2003-01-02|,
    first_day_of_month of |2003-01-02|
  ) in
  let x equals (
    a +! b,    # integer
    a +. b,    # decimal
    a +$ b,    # money
    a +^ b     # duration
  ) in
  0
```

# Metadata declaration

```catala
declaration structure Struct1:
  data fld1 content integer
  data fld2 content decimal

declaration enumeration Enum1:
  -- Case1 content integer
  -- Case2

declaration scope Scope1:
  internal var1 content integer
  internal var2 condition
  sub1 scope Scope0

  internal var1 content integer
  output var3 content integer
  input var4 content integer
  input output var5 content integer
  context var6 content integer
  context output var7 content integer
  output sub2 scope Scope0

  internal var1 content integer
    state before
    state after

declaration const content decimal
  equals 17.1

declaration square content decimal
  depends on x content decimal
  equals x * x
```

# Expressions

```catala
declaration x content integer equals
  let x equals let x equals 36 - 5 in 0
  in
  let x equals
    match expr with pattern
       -- Case1 of x : 0
       -- Case2 : 0
       -- anything : 0
  in
  let x equals
    expr with pattern Case1
  in
  let x equals
    expr with pattern Case1 of x
    and x >= 2
  in
  let x equals
    struc1 but replace { -- fld2: 8% }
  in
  let x equals
    struc1.fld2
  in
  let x equals
    tuple1.2
  in
  let x equals
    sub1.var0
  in
  let x equals
    f of $44.50, 1/3
  in
  let x equals
    output of Scope1 with
      { -- fld1: 9 -- fld2: 15% }
  in
  let x equals
    if 0 then 0 else 0
  in
  let x equals
    var1 state before
  in
  0
```

# Scope definition

```catala
scope Scope1:
  definition x equals 0

scope Scope1
  under condition var1 >= 2:

  definition var1 equals 0

  definition var1
    under condition 0
    consequence equals 0

  rule var2
    under condition var1 >= 2
    consequence fulfilled

  rule var2 under condition false
    consequence not fulfilled

  definition f of x, y equals 0

  label lbl1 definition var1 equals 0

  exception lbl1 definition var1 equals 0

  exception definition var1 equals 0

  definition var1
    state before
    equals 0

  assertion 0

  date round decreasing
```

# List operations

```catala
declaration x content integer equals
  let x equals
    lst contains 3
  in
  let x equals
    exists x among lst such that x > 2
  in
  let x equals
    for all x among lst we have x > 2
  in
  let x equals
    (x + 2) for x among lst
  in
  let x equals
    list of x among lst such that x > 2
  in
  let x equals
    (x - 2) for x among lst
      such that x > 2
  in
  let x equals
    (x + y) for (x, y) among (lst1, lst2)
  in
  let x equals
    lst1 ++ lst2
  in
  let x equals
    sum integer of lst
  in
  let x equals
    number of lst
  in
  let x equals
    maximum of lst
      or if list empty then -1
  in
  let x equals
    content of x among lst
      such that x * x is minimum
      or if list empty then -1
  in
  0
```


It's normal that the test below returns a resolution or type error, we just want
to ensure that the *syntax* is correct.

```catala-test-inline
$ catala typecheck
┌─[ERROR]─
│
│  No scope named Scope0 found
│
├─➤ doc/syntax/syntax_en.catala_en:94.14-94.20:
│    │
│ 94 │   sub1 scope Scope0
│    │              ‾‾‾‾‾‾
└─ Metadata declaration
#return code 123#
```