# Some useful helpers for dealing with text (arrays of characters)

# to-text-line gets called implicitly in various places
# define it to be identical to 'to-text' by default
def to-text-line x:_elem -> y:address:array:character [
  local-scope
  load-ingredients
  y <- to-text x
]

# variant for arrays (since we can't pass them around otherwise)
def array-to-text-line x:address:array:_elem -> y:address:array:character [
  local-scope
  load-ingredients
  y <- to-text *x
]

def equal a:address:array:character, b:address:array:character -> result:boolean [
  local-scope
  load-ingredients
  a-len:number <- length *a
  b-len:number <- length *b
  # compare lengths
  {
    trace 99, [text-equal], [comparing lengths]
    length-equal?:boolean <- equal a-len, b-len
    break-if length-equal?
    return 0
  }
  # compare each corresponding character
  trace 99, [text-equal], [comparing characters]
  i:number <- copy 0
  {
    done?:boolean <- greater-or-equal i, a-len
    break-if done?
    a2:character <- index *a, i
    b2:character <- index *b, i
    {
      chars-match?:boolean <- equal a2, b2
      break-if chars-match?
      return 0
    }
    i <- add i, 1
    loop
  }
  return 1
]

scenario text-equal-reflexive [
  run [
    local-scope
    x:address:array:character <- new [abc]
    10:boolean/raw <- equal x, x
  ]
  memory-should-contain [
    10 <- 1  # x == x for all x
  ]
]

scenario text-equal-identical [
  run [
    local-scope
    x:address:array:character <- new [abc]
    y:address:array:character <- new [abc]
    10:boolean/raw <- equal x, y
  ]
  memory-should-contain [
    10 <- 1  # abc == abc
  ]
]

scenario text-equal-distinct-lengths [
  run [
    local-scope
    x:address:array:character <- new [abc]
    y:address:array:character <- new [abcd]
    10:boolean/raw <- equal x, y
  ]
  memory-should-contain [
    10 <- 0  # abc != abcd
  ]
  trace-should-contain [
    text-equal: comparing lengths
  ]
  trace-should-not-contain [
    text-equal: comparing characters
  ]
]

scenario text-equal-with-empty [
  run [
    local-scope
    x:address:array:character <- new []
    y:address:array:character <- new [abcd]
    10:boolean/raw <- equal x, y
  ]
  memory-should-contain [
    10 <- 0  # "" != abcd
  ]
]

scenario text-equal-common-lengths-but-distinct [
  run [
    local-scope
    x:address:array:character <- new [abc]
    y:address:array:character <- new [abd]
    10:boolean/raw <- equal x, y
  ]
  memory-should-contain [
    10 <- 0  # abc != abd
  ]
]

# A new type to help incrementally construct texts.
container buffer [
  length:number
  data:address:array:character
]

def new-buffer capacity:number -> result:address:buffer [
  local-scope
  load-ingredients
  result <- new buffer:type
  *result <- put *result, length:offset, 0
  {
    break-if capacity
    # capacity not provided
    capacity <- copy 10
  }
  data:address:array:character <- new character:type, capacity
  *result <- put *result, data:offset, data
  return result
]

def grow-buffer in:address:buffer -> in:address:buffer [
  local-scope
  load-ingredients
  # double buffer size
  olddata:address:array:character <- get *in, data:offset
  oldlen:number <- length *olddata
  newlen:number <- multiply oldlen, 2
  newdata:address:array:character <- new character:type, newlen
  *in <- put *in, data:offset, newdata
  # copy old contents
  i:number <- copy 0
  {
    done?:boolean <- greater-or-equal i, oldlen
    break-if done?
    src:character <- index *olddata, i
    *newdata <- put-index *newdata, i, src
    i <- add i, 1
    loop
  }
]

def buffer-full? in:address:buffer -> result:boolean [
  local-scope
  load-ingredients
  len:number <- get *in, length:offset
  s:address:array:character <- get *in, data:offset
  capacity:number <- length *s
  result <- greater-or-equal len, capacity
]

# most broadly applicable definition of append to a buffer: just call to-text
def append buf:address:buffer, x:_elem -> buf:address:buffer [
  local-scope
  load-ingredients
  text:address:array:character <- to-text x
  len:number <- length *text
  i:number <- copy 0
  {
    done?:boolean <- greater-or-equal i, len
    break-if done?
    c:character <- index *text, i
    buf <- append buf, c
    i <- add i, 1
    loop
  }
]

def append in:address:buffer, c:character -> in:address:buffer [
  local-scope
  load-ingredients
  len:number <- get *in, length:offset
  {
    # backspace? just drop last character if it exists and return
    backspace?:boolean <- equal c, 8/backspace
    break-unless backspace?
    empty?:boolean <- lesser-or-equal len, 0
    return-if empty?
    len <- subtract len, 1
    *in <- put *in, length:offset, len
    return
  }
  {
    # grow buffer if necessary
    full?:boolean <- buffer-full? in
    break-unless full?
    in <- grow-buffer in
  }
  s:address:array:character <- get *in, data:offset
  *s <- put-index *s, len, c
  len <- add len, 1
  *in <- put *in, length:offset, len
]

scenario buffer-append-works [
  run [
    local-scope
    x:address:buffer <- new-buffer 3
    s1:address:array:character <- get *x, data:offset
    c:character <- copy 97/a
    x <- append x, c
    c:character <- copy 98/b
    x <- append x, c
    c:character <- copy 99/c
    x <- append x, c
    s2:address:array:character <- get *x, data:offset
    10:boolean/raw <- equal s1, s2
    11:array:character/raw <- copy *s2
    +buffer-filled
    c:character <- copy 100/d
    x <- append x, c
    s3:address:array:character <- get *x, data:offset
    20:boolean/raw <- equal s1, s3
    21:number/raw <- get *x, length:offset
    30:array:character/raw <- copy *s3
  ]
  memory-should-contain [
    # before +buffer-filled
    10 <- 1   # no change in data pointer
    11 <- 3   # size of data
    12 <- 97  # data
    13 <- 98
    14 <- 99
    # in the end
    20 <- 0   # data pointer has grown
    21 <- 4   # final length
    30 <- 6   # but data's capacity has doubled
    31 <- 97  # data
    32 <- 98
    33 <- 99
    34 <- 100
    35 <- 0
    36 <- 0
  ]
]

scenario buffer-append-to-empty [
  run [
    local-scope
    x:address:buffer <- new-buffer
    c:character <- copy 97/a
    x <- append x, c
  ]
]

scenario buffer-append-handles-backspace [
  run [
    local-scope
    x:address:buffer <- new-buffer 3
    c:character <- copy 97/a
    x <- append x, c
    c:character <- copy 98/b
    x <- append x, c
    c:character <- copy 8/backspace
    x <- append x, c
    s:address:array:character <- buffer-to-array x
    10:array:character/raw <- copy *s
  ]
  memory-should-contain [
    10 <- 1   # length
    11 <- 97  # contents
    12 <- 0
  ]
]

def buffer-to-array in:address:buffer -> result:address:array:character [
  local-scope
  load-ingredients
  {
    # propagate null buffer
    break-if in
    return 0
  }
  len:number <- get *in, length:offset
  s:address:array:character <- get *in, data:offset
  # we can't just return s because it is usually the wrong length
  result <- new character:type, len
  i:number <- copy 0
  {
    done?:boolean <- greater-or-equal i, len
    break-if done?
    src:character <- index *s, i
    *result <- put-index *result, i, src
    i <- add i, 1
    loop
  }
]

def append a:address:array:character, b:address:array:character -> result:address:array:character [
  local-scope
  load-ingredients
  # handle null addresses
  return-unless a, b
  return-unless b, a
  # result = new character[a.length + b.length]
  a-len:number <- length *a
  b-len:number <- length *b
  result-len:number <- add a-len, b-len
  result <- new character:type, result-len
  # copy a into result
  result-idx:number <- copy 0
  i:number <- copy 0
  {
    # while i < a.length
    a-done?:boolean <- greater-or-equal i, a-len
    break-if a-done?
    # result[result-idx] = a[i]
    in:character <- index *a, i
    *result <- put-index *result, result-idx, in
    i <- add i, 1
    result-idx <- add result-idx, 1
    loop
  }
  # copy b into result
  i <- copy 0
  {
    # while i < b.length
    b-done?:boolean <- greater-or-equal i, b-len
    break-if b-done?
    # result[result-idx] = a[i]
    in:character <- index *b, i
    *result <- put-index *result, result-idx, in
    i <- add i, 1
    result-idx <- add result-idx, 1
    loop
  }
]

scenario text-append-1 [
  run [
    local-scope
    x:address:array:character <- new [hello,]
    y:address:array:character <- new [ world!]
    z:address:array:character <- append x, y
    10:array:character/raw <- copy *z
  ]
  memory-should-contain [
    10:array:character <- [hello, world!]
  ]
]

scenario text-append-null [
  run [
    local-scope
    x:address:array:character <- copy 0
    y:address:array:character <- new [ world!]
    z:address:array:character <- append x, y
    10:array:character/raw <- copy *z
  ]
  memory-should-contain [
    10:array:character <- [ world!]
  ]
]

scenario text-append-null-2 [
  run [
    local-scope
    x:address:array:character <- new [hello,]
    y:address:array:character <- copy 0
    z:address:array:character <- append x, y
    10:array:character/raw <- copy *z
  ]
  memory-should-contain [
    10:array:character <- [hello,]
  ]
]

scenario replace-character-in-text [
  run [
    local-scope
    x:address:array:character <- new [abc]
    x <- replace x, 98/b, 122/z
    10:array:character/raw <- copy *x
  ]
  memory-should-contain [
    10:array:character <- [azc]
  ]
]

def replace s:address:array:character, oldc:character, newc:character, from:number/optional -> s:address:array:character [
  local-scope
  load-ingredients
  len:number <- length *s
  i:number <- find-next s, oldc, from
  done?:boolean <- greater-or-equal i, len
  return-if done?, s/same-as-ingredient:0
  *s <- put-index *s, i, newc
  i <- add i, 1
  s <- replace s, oldc, newc, i
]

scenario replace-character-at-start [
  run [
    local-scope
    x:address:array:character <- new [abc]
    x <- replace x, 97/a, 122/z
    10:array:character/raw <- copy *x
  ]
  memory-should-contain [
    10:array:character <- [zbc]
  ]
]

scenario replace-character-at-end [
  run [
    local-scope
    x:address:array:character <- new [abc]
    x <- replace x, 99/c, 122/z
    10:array:character/raw <- copy *x
  ]
  memory-should-contain [
    10:array:character <- [abz]
  ]
]

scenario replace-character-missing [
  run [
    local-scope
    x:address:array:character <- new [abc]
    x <- replace x, 100/d, 122/z
    10:array:character/raw <- copy *x
  ]
  memory-should-contain [
    10:array:character <- [abc]
  ]
]

scenario replace-all-characters [
  run [
    local-scope
    x:address:array:character <- new [banana]
    x <- replace x, 97/a, 122/z
    10:array:character/raw <- copy *x
  ]
  memory-should-contain [
    10:array:character <- [bznznz]
  ]
]

# replace underscores in first with remaining args
def interpolate template:address:array:character -> result:address:array:character [
  local-scope
  load-ingredients  # consume just the template
  # compute result-len, space to allocate for result
  tem-len:number <- length *template
  result-len:number <- copy tem-len
  {
    # while ingredients remain
    a:address:array:character, arg-received?:boolean <- next-ingredient
    break-unless arg-received?
    # result-len = result-len + arg.length - 1 (for the 'underscore' being replaced)
    a-len:number <- length *a
    result-len <- add result-len, a-len
    result-len <- subtract result-len, 1
    loop
  }
  rewind-ingredients
  _ <- next-ingredient  # skip template
  result <- new character:type, result-len
  # repeatedly copy sections of template and 'holes' into result
  result-idx:number <- copy 0
  i:number <- copy 0
  {
    # while arg received
    a:address:array:character, arg-received?:boolean <- next-ingredient
    break-unless arg-received?
    # copy template into result until '_'
    {
      # while i < template.length
      tem-done?:boolean <- greater-or-equal i, tem-len
      break-if tem-done?, +done:label
      # while template[i] != '_'
      in:character <- index *template, i
      underscore?:boolean <- equal in, 95/_
      break-if underscore?
      # result[result-idx] = template[i]
      *result <- put-index *result, result-idx, in
      i <- add i, 1
      result-idx <- add result-idx, 1
      loop
    }
    # copy 'a' into result
    j:number <- copy 0
    {
      # while j < a.length
      arg-done?:boolean <- greater-or-equal j, a-len
      break-if arg-done?
      # result[result-idx] = a[j]
      in:character <- index *a, j
      *result <- put-index *result, result-idx, in
      j <- add j, 1
      result-idx <- add result-idx, 1
      loop
    }
    # skip '_' in template
    i <- add i, 1
    loop  # interpolate next arg
  }
  +done
  # done with holes; copy rest of template directly into result
  {
    # while i < template.length
    tem-done?:boolean <- greater-or-equal i, tem-len
    break-if tem-done?
    # result[result-idx] = template[i]
    in:character <- index *template, i
    *result <- put-index *result, result-idx, in
    i <- add i, 1
    result-idx <- add result-idx, 1
    loop
  }
]

scenario interpolate-works [
  run [
    local-scope
    x:address:array:character <- new [abc_ghi]
    y:address:array:character <- new [def]
    z:address:array:character <- interpolate x, y
    10:array:character/raw <- copy *z
  ]
  memory-should-contain [
    10:array:character <- [abcdefghi]
  ]
]

scenario interpolate-at-start [
  run [
    local-scope
    x:address:array:character <- new [_, hello!]
    y:address:array:character <- new [abc]
    z:address:array:character <- interpolate x, y
    10:array:character/raw <- copy *z
  ]
  memory-should-contain [
    10:array:character <- [abc, hello!]
    22 <- 0  # out of bounds
  ]
]

scenario interpolate-at-end [
  run [
    x:address:array:character <- new [hello, _]
    y:address:array:character <- new [abc]
    z:address:array:character <- interpolate x, y
    10:array:character/raw <- copy *z
  ]
  memory-should-contain [
    10:array:character <- [hello, abc]
  ]
]

# result:boolean <- space? c:character
def space? c:character -> result:boolean [
  local-scope
  load-ingredients
  # most common case first
  result <- equal c, 32/space
  return-if result
  result <- equal c, 10/newline
  return-if result
  result <- equal c, 9/tab
  return-if result
  result <- equal c, 13/carriage-return
  return-if result
  # remaining uncommon cases in sorted order
  # http://unicode.org code-points in unicode-set Z and Pattern_White_Space
  result <- equal c, 11/ctrl-k
  return-if result
  result <- equal c, 12/ctrl-l
  return-if result
  result <- equal c, 133/ctrl-0085
  return-if result
  result <- equal c, 160/no-break-space
  return-if result
  result <- equal c, 5760/ogham-space-mark
  return-if result
  result <- equal c, 8192/en-quad
  return-if result
  result <- equal c, 8193/em-quad
  return-if result
  result <- equal c, 8194/en-space
  return-if result
  result <- equal c, 8195/em-space
  return-if result
  result <- equal c, 8196/three-per-em-space
  return-if result
  result <- equal c, 8197/four-per-em-space
  return-if result
  result <- equal c, 8198/six-per-em-space
  return-if result
  result <- equal c, 8199/figure-space
  return-if result
  result <- equal c, 8200/punctuation-space
  return-if result
  result <- equal c, 8201/thin-space
  return-if result
  result <- equal c, 8202/hair-space
  return-if result
  result <- equal c, 8206/left-to-right
  return-if result
  result <- equal c, 8207/right-to-left
  return-if result
  result <- equal c, 8232/line-separator
  return-if result
  result <- equal c, 8233/paragraph-separator
  return-if result
  result <- equal c, 8239/narrow-no-break-space
  return-if result
  result <- equal c, 8287/medium-mathematical-space
  return-if result
  result <- equal c, 12288/ideographic-space
]

def trim s:address:array:character -> result:address:array:character [
  local-scope
  load-ingredients
  len:number <- length *s
  # left trim: compute start
  start:number <- copy 0
  {
    {
      at-end?:boolean <- greater-or-equal start, len
      break-unless at-end?
      result <- new character:type, 0
      return
    }
    curr:character <- index *s, start
    whitespace?:boolean <- space? curr
    break-unless whitespace?
    start <- add start, 1
    loop
  }
  # right trim: compute end
  end:number <- subtract len, 1
  {
    not-at-start?:boolean <- greater-than end, start
    assert not-at-start?, [end ran up against start]
    curr:character <- index *s, end
    whitespace?:boolean <- space? curr
    break-unless whitespace?
    end <- subtract end, 1
    loop
  }
  # result = new character[end+1 - start]
  new-len:number <- subtract end, start, -1
  result:address:array:character <- new character:type, new-len
  # copy the untrimmed parts between start and end
  i:number <- copy start
  j:number <- copy 0
  {
    # while i <= end
    done?:boolean <- greater-than i, end
    break-if done?
    # result[j] = s[i]
    src:character <- index *s, i
    *result <- put-index *result, j, src
    i <- add i, 1
    j <- add j, 1
    loop
  }
]

scenario trim-unmodified [
  run [
    local-scope
    x:address:array:character <- new [abc]
    y:address:array:character <- trim x
    1:array:character/raw <- copy *y
  ]
  memory-should-contain [
    1:array:character <- [abc]
  ]
]

scenario trim-left [
  run [
    local-scope
    x:address:array:character <- new [  abc]
    y:address:array:character <- trim x
    1:array:character/raw <- copy *y
  ]
  memory-should-contain [
    1:array:character <- [abc]
  ]
]

scenario trim-right [
  run [
    local-scope
    x:address:array:character <- new [abc  ]
    y:address:array:character <- trim x
    1:array:character/raw <- copy *y
  ]
  memory-should-contain [
    1:array:character <- [abc]
  ]
]

scenario trim-left-right [
  run [
    local-scope
    x:address:array:character <- new [  abc   ]
    y:address:array:character <- trim x
    1:array:character/raw <- copy *y
  ]
  memory-should-contain [
    1:array:character <- [abc]
  ]
]

scenario trim-newline-tab [
  run [
    local-scope
    x:address:array:character <- new [	abc
]
    y:address:array:character <- trim x
    1:array:character/raw <- copy *y
  ]
  memory-should-contain [
    1:array:character <- [abc]
  ]
]

def find-next text:address:array:character, pattern:character, idx:number -> next-index:number [
  local-scope
  load-ingredients
  len:number <- length *text
  {
    eof?:boolean <- greater-or-equal idx, len
    break-if eof?
    curr:character <- index *text, idx
    found?:boolean <- equal curr, pattern
    break-if found?
    idx <- add idx, 1
    loop
  }
  return idx
]

scenario text-find-next [
  run [
    local-scope
    x:address:array:character <- new [a/b]
    10:number/raw <- find-next x, 47/slash, 0/start-index
  ]
  memory-should-contain [
    10 <- 1
  ]
]

scenario text-find-next-empty [
  run [
    local-scope
    x:address:array:character <- new []
    10:number/raw <- find-next x, 47/slash, 0/start-index
  ]
  memory-should-contain [
    10 <- 0
  ]
]

scenario text-find-next-initial [
  run [
    local-scope
    x:address:array:character <- new [/abc]
    10:number/raw <- find-next x, 47/slash, 0/start-index
  ]
  memory-should-contain [
    10 <- 0  # prefix match
  ]
]

scenario text-find-next-final [
  run [
    local-scope
    x:address:array:character <- new [abc/]
    10:number/raw <- find-next x, 47/slash, 0/start-index
  ]
  memory-should-contain [
    10 <- 3  # suffix match
  ]
]

scenario text-find-next-missing [
  run [
    local-scope
    x:address:array:character <- new [abcd]
    10:number/raw <- find-next x, 47/slash, 0/start-index
  ]
  memory-should-contain [
    10 <- 4  # no match
  ]
]

scenario text-find-next-invalid-index [
  run [
    local-scope
    x:address:array:character <- new [abc]
    10:number/raw <- find-next x, 47/slash, 4/start-index
  ]
  memory-should-contain [
    10 <- 4  # no change
  ]
]

scenario text-find-next-first [
  run [
    local-scope
    x:address:array:character <- new [ab/c/]
    10:number/raw <- find-next x, 47/slash, 0/start-index
  ]
  memory-should-contain [
    10 <- 2  # first '/' of multiple
  ]
]

scenario text-find-next-second [
  run [
    local-scope
    x:address:array:character <- new [ab/c/]
    10:number/raw <- find-next x, 47/slash, 3/start-index
  ]
  memory-should-contain [
    10 <- 4  # second '/' of multiple
  ]
]

# search for a pattern of multiple characters
# fairly dumb algorithm
def find-next text:address:array:character, pattern:address:array:character, idx:number -> next-index:number [
  local-scope
  load-ingredients
  first:character <- index *pattern, 0
  # repeatedly check for match at current idx
  len:number <- length *text
  {
    # does some unnecessary work checking even when there isn't enough of text left
    done?:boolean <- greater-or-equal idx, len
    break-if done?
    found?:boolean <- match-at text, pattern, idx
    break-if found?
    idx <- add idx, 1
    # optimization: skip past indices that definitely won't match
    idx <- find-next text, first, idx
    loop
  }
  return idx
]

scenario find-next-text-1 [
  run [
    local-scope
    x:address:array:character <- new [abc]
    y:address:array:character <- new [bc]
    10:number/raw <- find-next x, y, 0
  ]
  memory-should-contain [
    10 <- 1
  ]
]

scenario find-next-text-2 [
  run [
    local-scope
    x:address:array:character <- new [abcd]
    y:address:array:character <- new [bc]
    10:number/raw <- find-next x, y, 1
  ]
  memory-should-contain [
    10 <- 1
  ]
]

scenario find-next-no-match [
  run [
    local-scope
    x:address:array:character <- new [abc]
    y:address:array:character <- new [bd]
    10:number/raw <- find-next x, y, 0
  ]
  memory-should-contain [
    10 <- 3  # not found
  ]
]

scenario find-next-suffix-match [
  run [
    lo<style>pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span><span class="c1">//: Ingredients of a recipe are meant to be immutable unless they&#39;re also</span>
<span class="c1">//: products. This layer will start enforcing this check.</span>
<span class="c1">//:</span>
<span class="c1">//: One hole for now: variables in surrounding spaces are implicitly mutable.</span>

<span class="o">:</span><span class="p">(</span><span class="n">scenario</span><span class="w"> </span><span class="n">can_modify_ingredients_that_are_also_products</span><span class="p">)</span>
<span class="cp"># mutable container</span>
<span class="n">def</span><span class="w"> </span><span class="n">main</span><span class="w"> </span><span class="p">[</span>
<span class="w">  </span><span class="n">local</span><span class="o">-</span><span class="n">scope</span>
<span class="w">  </span><span class="nl">p</span><span class="p">:</span><span class="n">point</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="n">merge</span><span class="w"> </span><span class="mi">34</span><span class="p">,</span><span class="w"> </span><span class="mi">35</span>
<span class="w">  </span><span class="n">p</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="n">foo</span><span class="w"> </span><span class="n">p</span>
<span class="p">]</span>
<span class="n">def</span><span class="w"> </span><span class="n">foo</span><span class="w"> </span><span class="n">p</span><span class="o">:</span><span class="n">point</span><span class="w"> </span><span class="o">-&gt;</span><span class="w"> </span><span class="n">p</span><span class="o">:</span><span class="n">point</span><span class="w"> </span><span class="p">[</span>
<span class="w">  </span><span class="n">local</span><span class="o">-</span><span class="n">scope</span>
<span class="w">  </span><span class="n">load</span><span class="o">-</span><span class="n">ingredients</span>
<span class="w">  </span><span class="n">p</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="n">put</span><span class="w"> </span><span class="n">p</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="o">:</span><span class="n">offset</span><span class="p">,</span><span class="w"> </span><span class="mi">34</span>
<span class="p">]</span>
<span class="nl">$error</span><span class="p">:</span><span class="w"> </span><span class="mi">0</span>

<span class="o">:</span><span class="p">(</span><span class="n">scenario</span><span class="w"> </span><span class="n">can_modify_ingredients_that_are_also_products_2</span><span class="p">)</span>
<span class="n">def</span><span class="w"> </span><span class="n">main</span><span class="w"> </span><span class="p">[</span>
<span class="w">  </span><span class="n">local</span><span class="o">-</span><span class="n">scope</span>
<span class="w">  </span><span class="nl">p</span><span class="p">:</span><span class="n">address</span><span class="o">:</span><span class="n">point</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">point</span><span class="o">:</span><span class="n">type</span>
<span class="w">  </span><span class="n">p</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="n">foo</span><span class="w"> </span><span class="n">p</span>
<span class="p">]</span>
<span class="cp"># mutable address to container</span>
<span class="n">def</span><span class="w"> </span><span class="n">foo</span><span class="w"> </span><span class="n">p</span><span class="o">:</span><span class="n">address</span><span class="o">:</span><span class="n">point</span><span class="w"> </span><span class="o">-&gt;</span><span class="w"> </span><span class="n">p</span><span class="o">:</span><span class="n">address</span><span class="o">:</span><span class="n">point</span><span class="w"> </span><span class="p">[</span>
<span class="w">  </span><span class="n">local</span><span class="o">-</span><span class="n">scope</span>
<span class="w">  </span><span class="n">load</span><span class="o">-