From f8b9e5c0dccd1563764426878ba0f2f982c3f310 Mon Sep 17 00:00:00 2001
From: "Kartik K. Agaram" <vc@akkartik.com>
Date: Mon, 12 Sep 2016 09:23:56 -0700
Subject: 3340

Rename files to be consistent with my (forgotten) convention of always
using underscores over hyphens.

I'll leave server-socket.mu alone for now, since Stephen's hacking on
it.
---
 immutable-error.mu |  13 --
 immutable_error.mu |  13 ++
 lambda-to-mu.mu    | 584 -----------------------------------------------------
 lambda_to_mu.mu    | 584 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 real-files.mu      |  18 --
 real_files.mu      |  18 ++
 6 files changed, 615 insertions(+), 615 deletions(-)
 delete mode 100644 immutable-error.mu
 create mode 100644 immutable_error.mu
 delete mode 100644 lambda-to-mu.mu
 create mode 100644 lambda_to_mu.mu
 delete mode 100644 real-files.mu
 create mode 100644 real_files.mu

diff --git a/immutable-error.mu b/immutable-error.mu
deleted file mode 100644
index b75e2791..00000000
--- a/immutable-error.mu
+++ /dev/null
@@ -1,13 +0,0 @@
-# compare mutable.mu
-
-def main [
-  local-scope
-  x:address:number <- new number:type
-  foo x
-]
-
-def foo x:address:number [
-  local-scope
-  load-ingredients
-  *x <- copy 34  # will cause an error because x is immutable in this function
-]
diff --git a/immutable_error.mu b/immutable_error.mu
new file mode 100644
index 00000000..b75e2791
--- /dev/null
+++ b/immutable_error.mu
@@ -0,0 +1,13 @@
+# compare mutable.mu
+
+def main [
+  local-scope
+  x:address:number <- new number:type
+  foo x
+]
+
+def foo x:address:number [
+  local-scope
+  load-ingredients
+  *x <- copy 34  # will cause an error because x is immutable in this function
+]
diff --git a/lambda-to-mu.mu b/lambda-to-mu.mu
deleted file mode 100644
index ed3cd72c..00000000
--- a/lambda-to-mu.mu
+++ /dev/null
@@ -1,584 +0,0 @@
-## experimental compiler to translate programs written in a generic
-## expression-oriented language called 'lambda' into mu
-
-scenario convert-lambda [
-  run [
-    local-scope
-    1:text/raw <- lambda-to-mu [(add a (multiply b c))]
-    2:array:character/raw <- copy *1:text/raw
-  ]
-  memory-should-contain [
-    2:array:character <- [t1 <- multiply b c
-result <- add a t1]
-  ]
-]
-
-def lambda-to-mu in:address:array:character -> out:address:array:character [
-  local-scope
-  load-ingredients
-  out <- copy 0
-  cells:address:cell <- parse in
-  out <- to-mu cells
-]
-
-# 'parse' will turn lambda expressions into trees made of cells
-exclusive-container cell [
-  atom:text
-  pair:pair
-]
-
-# printed below as < first | rest >
-container pair [
-  first:address:cell
-  rest:address:cell
-]
-
-def new-atom name:address:array:character -> result:address:cell [
-  local-scope
-  load-ingredients
-  result <- new cell:type
-  *result <- merge 0/tag:atom, name
-]
-
-def new-pair a:address:cell, b:address:cell -> result:address:cell [
-  local-scope
-  load-ingredients
-  result <- new cell:type
-  *result <- merge 1/tag:pair, a/first, b/rest
-]
-
-def is-atom? x:address:cell -> result:boolean [
-  local-scope
-  load-ingredients
-  reply-unless x, 0/false
-  _, result <- maybe-convert *x, atom:variant
-]
-
-def is-pair? x:address:cell -> result:boolean [
-  local-scope
-  load-ingredients
-  reply-unless x, 0/false
-  _, result <- maybe-convert *x, pair:variant
-]
-
-scenario atom-is-not-pair [
-  local-scope
-  s:text <- new [a]
-  x:address:cell <- new-atom s
-  10:boolean/raw <- is-atom? x
-  11:boolean/raw <- is-pair? x
-  memory-should-contain [
-    10 <- 1
-    11 <- 0
-  ]
-]
-
-scenario pair-is-not-atom [
-  local-scope
-  # construct (a . nil)
-  s:text <- new [a]
-  x:address:cell <- new-atom s
-  y:address:cell <- new-pair x, 0/nil
-  10:boolean/raw <- is-atom? y
-  11:boolean/raw <- is-pair? y
-  memory-should-contain [
-    10 <- 0
-    11 <- 1
-  ]
-]
-
-def atom-match? x:address:cell, pat:address:array:character -> result:boolean [
-  local-scope
-  load-ingredients
-  s:text, is-atom?:boolean <- maybe-convert *x, atom:variant
-  reply-unless is-atom?, 0/false
-  result <- equal pat, s
-]
-
-scenario atom-match [
-  local-scope
-  x:address:cell <- new-atom [abc]
-  10:boolean/raw <- atom-match? x, [abc]
-  memory-should-contain [
-    10 <- 1
-  ]
-]
-
-def first x:address:cell -> result:address:cell [
-  local-scope
-  load-ingredients
-  pair:pair, pair?:boolean <- maybe-convert *x, pair:variant
-  reply-unless pair?, 0/nil
-  result <- get pair, first:offset
-]
-
-def rest x:address:cell -> result:address:cell [
-  local-scope
-  load-ingredients
-  pair:pair, pair?:boolean <- maybe-convert *x, pair:variant
-  reply-unless pair?, 0/nil
-  result <- get pair, rest:offset
-]
-
-def set-first base:address:cell, new-first:address:cell -> base:address:cell [
-  local-scope
-  load-ingredients
-  pair:pair, is-pair?:boolean <- maybe-convert *base, pair:variant
-  reply-unless is-pair?
-  pair <- put pair, first:offset, new-first
-  *base <- merge 1/pair, pair
-]
-
-def set-rest base:address:cell, new-rest:address:cell -> base:address:cell [
-  local-scope
-  load-ingredients
-  pair:pair, is-pair?:boolean <- maybe-convert *base, pair:variant
-  reply-unless is-pair?
-  pair <- put pair, rest:offset, new-rest
-  *base <- merge 1/pair, pair
-]
-
-scenario cell-operations-on-atom [
-  local-scope
-  s:text <- new [a]
-  x:address:cell <- new-atom s
-  10:address:cell/raw <- first x
-  11:address:cell/raw <- rest x
-  memory-should-contain [
-    10 <- 0  # first is nil
-    11 <- 0  # rest is nil
-  ]
-]
-
-scenario cell-operations-on-pair [
-  local-scope
-  # construct (a . nil)
-  s:text <- new [a]
-  x:address:cell <- new-atom s
-  y:address:cell <- new-pair x, 0/nil
-  x2:address:cell <- first y
-  10:boolean/raw <- equal x, x2
-  11:address:cell/raw <- rest y
-  memory-should-contain [
-    10 <- 1  # first is correct
-    11 <- 0  # rest is nil
-  ]
-]
-
-## convert lambda text to a tree of cells
-
-def parse in:address:array:character -> out:address:cell [
-  local-scope
-  load-ingredients
-  s:address:stream:character <- new-stream in
-  out, s <- parse s
-  trace 2, [app/parse], out
-]
-
-def parse in:address:stream:character -> out:address:cell, in:address:stream:character [
-  local-scope
-  load-ingredients
-  # skip whitespace
-  in <- skip-whitespace in
-  c:character, eof?:boolean <- peek in
-  reply-if eof?, 0/nil
-  pair?:boolean <- equal c, 40/open-paren
-  {
-    break-if pair?
-    # atom
-    b:address:buffer <- new-buffer 30
-    {
-      done?:boolean <- end-of-stream? in
-      break-if done?
-      # stop before close paren or space
-      c:character <- peek in
-      done? <- equal c, 41/close-paren
-      break-if done?
-      done? <- space? c
-      break-if done?
-      c <- read in
-      b <- append b, c
-      loop
-    }
-    s:text <- buffer-to-array b
-    out <- new-atom s
-  }
-  {
-    break-unless pair?
-    # pair
-    read in  # skip the open-paren
-    out <- new cell:type  # start out with nil
-    # read in first element of pair
-    {
-      end?:boolean <- end-of-stream? in
-      not-end?:boolean <- not end?
-      assert not-end?, [unbalanced '(' in expression]
-      c <- peek in
-      close-paren?:boolean <- equal c, 41/close-paren
-      break-if close-paren?
-      first:address:cell, in <- parse in
-      *out <- merge 1/pair, first, 0/nil
-    }
-    # read in any remaining elements
-    curr:address:cell <- copy out
-    {
-      in <- skip-whitespace in
-      end?:boolean <- end-of-stream? in
-      not-end?:boolean <- not end?
-      assert not-end?, [unbalanced '(' in expression]
-      # termination check: ')'
-      c <- peek in
-      {
-        close-paren?:boolean <- equal c, 41/close-paren
-        break-unless close-paren?
-        read in  # skip ')'
-        break +end-pair:label
-      }
-      # still here? read next element of pair
-      next:address:cell, in <- parse in
-      is-dot?:boolean <- atom-match? next, [.]
-      {
-        break-if is-dot?
-        next-curr:address:cell <- new-pair next, 0/nil
-        curr <- set-rest curr, next-curr
-        curr <- rest curr
-      }
-      {
-        break-unless is-dot?
-        # deal with dotted pair
-        in <- skip-whitespace in
-        c <- peek in
-        not-close-paren?:boolean <- not-equal c, 41/close-paren
-        assert not-close-paren?, [')' cannot immediately follow '.']
-        final:address:cell <- parse in
-        curr <- set-rest curr, final
-        # we're not gonna update curr, so better make sure the next iteration
-        # is going to end the pair
-        in <- skip-whitespace in
-        c <- peek in
-        close-paren?:boolean <- equal c, 41/close-paren
-        assert close-paren?, ['.' must be followed by exactly one expression before ')']
-      }
-      loop
-    }
-    +end-pair
-  }
-]
-
-def skip-whitespace in:address:stream:character -> in:address:stream:character [
-  local-scope
-  load-ingredients
-  {
-    done?:boolean <- end-of-stream? in
-    reply-if done?, 0/null
-    c:character <- peek in
-    space?:boolean <- space? c
-    break-unless space?
-    read in  # skip
-    loop
-  }
-]
-
-def to-text x:address:cell -> out:address:array:character [
-  local-scope
-  load-ingredients
-  buf:address:buffer <- new-buffer 30
-  buf <- to-buffer x, buf
-  out <- buffer-to-array buf
-]
-
-def to-buffer x:address:cell, buf:address:buffer -> buf:address:buffer [
-  local-scope
-  load-ingredients
-  # base case: empty cell
-  {
-    break-if x
-    buf <- append buf, [<>]
-    reply
-  }
-  # base case: atom
-  {
-    s:text, atom?:boolean <- maybe-convert *x, atom:variant
-    break-unless atom?
-    buf <- append buf, s
-    reply
-  }
-  # recursive case: pair
-  buf <- append buf, [< ]
-  first:address:cell <- first x
-  buf <- to-buffer first, buf
-  buf <- append buf, [ | ]
-  rest:address:cell <- rest x
-  buf <- to-buffer rest, buf
-  buf <- append buf, [ >]
-]
-
-scenario parse-single-letter-atom [
-  local-scope
-  s:text <- new [a]
-  x:address:cell <- parse s
-  s2:text, 10:boolean/raw <- maybe-convert *x, atom:variant
-  11:array:character/raw <- copy *s2
-  memory-should-contain [
-    10 <- 1  # parse result is an atom
-    11:array:character <- [a]
-  ]
-]
-
-scenario parse-atom [
-  local-scope
-  s:text <- new [abc]
-  x:address:cell <- parse s
-  s2:text, 10:boolean/raw <- maybe-convert *x, atom:variant
-  11:array:character/raw <- copy *s2
-  memory-should-contain [
-    10 <- 1  # parse result is an atom
-    11:array:character <- [abc]
-  ]
-]
-
-scenario parse-list-of-two-atoms [
-  local-scope
-  s:text <- new [(abc def)]
-  x:address:cell <- parse s
-  trace-should-contain [
-    app/parse: < abc | < def | <> > >
-  ]
-  10:boolean/raw <- is-pair? x
-  x1:address:cell <- first x
-  x2:address:cell <- rest x
-  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
-  12:boolean/raw <- is-pair? x2
-  x3:address:cell <- first x2
-  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
-  14:address:cell/raw <- rest x2
-  20:array:character/raw <- copy *s1
-  30:array:character/raw <- copy *s2
-  memory-should-contain [
-    10 <- 1  # parse result is a pair
-    11 <- 1  # result.first is an atom
-    12 <- 1  # result.rest is a pair
-    13 <- 1  # result.rest.first is an atom
-    14 <- 0  # result.rest.rest is nil
-    20:array:character <- [abc]  # result.first
-    30:array:character <- [def]  # result.rest.first
-  ]
-]
-
-scenario parse-list-with-extra-spaces [
-  local-scope
-  s:text <- new [ ( abc  def ) ]  # extra spaces
-  x:address:cell <- parse s
-  trace-should-contain [
-    app/parse: < abc | < def | <> > >
-  ]
-  10:boolean/raw <- is-pair? x
-  x1:address:cell <- first x
-  x2:address:cell <- rest x
-  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
-  12:boolean/raw <- is-pair? x2
-  x3:address:cell <- first x2
-  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
-  14:address:cell/raw <- rest x2
-  20:array:character/raw <- copy *s1
-  30:array:character/raw <- copy *s2
-  memory-should-contain [
-    10 <- 1  # parse result is a pair
-    11 <- 1  # result.first is an atom
-    12 <- 1  # result.rest is a pair
-    13 <- 1  # result.rest.first is an atom
-    14 <- 0  # result.rest.rest is nil
-    20:array:character <- [abc]  # result.first
-    30:array:character <- [def]  # result.rest.first
-  ]
-]
-
-scenario parse-list-of-more-than-two-atoms [
-  local-scope
-  s:text <- new [(abc def ghi)]
-  x:address:cell <- parse s
-  trace-should-contain [
-    app/parse: < abc | < def | < ghi | <> > > >
-  ]
-  10:boolean/raw <- is-pair? x
-  x1:address:cell <- first x
-  x2:address:cell <- rest x
-  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
-  12:boolean/raw <- is-pair? x2
-  x3:address:cell <- first x2
-  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
-  x4:address:cell <- rest x2
-  14:boolean/raw <- is-pair? x4
-  x5:address:cell <- first x4
-  s3:text, 15:boolean/raw <- maybe-convert *x5, atom:variant
-  16:address:cell/raw <- rest x4
-  20:array:character/raw <- copy *s1
-  30:array:character/raw <- copy *s2
-  40:array:character/raw <- copy *s3
-  memory-should-contain [
-    10 <- 1  # parse result is a pair
-    11 <- 1  # result.first is an atom
-    12 <- 1  # result.rest is a pair
-    13 <- 1  # result.rest.first is an atom
-    14 <- 1  # result.rest.rest is a pair
-    15 <- 1  # result.rest.rest.first is an atom
-    16 <- 0  # result.rest.rest.rest is nil
-    20:array:character <- [abc]  # result.first
-    30:array:character <- [def]  # result.rest.first
-    40:array:character <- [ghi]  # result.rest.rest
-  ]
-]
-
-scenario parse-nested-list [
-  local-scope
-  s:text <- new [((abc))]
-  x:address:cell <- parse s
-  trace-should-contain [
-    app/parse: < < abc | <> > | <> >
-  ]
-  10:boolean/raw <- is-pair? x
-  x1:address:cell <- first x
-  11:boolean/raw <- is-pair? x
-  x2:address:cell <- first x1
-  s1:text, 12:boolean/raw <- maybe-convert *x2, atom:variant
-  13:address:cell/raw <- rest x1
-  14:address:cell/raw <- rest x
-  20:array:character/raw <- copy *s1
-  memory-should-contain [
-    10 <- 1  # parse result is a pair
-    11 <- 1  # result.first is a pair
-    12 <- 1  # result.first.first is an atom
-    13 <- 0  # result.first.rest is nil
-    14 <- 0  # result.rest is nil
-    20:array:character <- [abc]  # result.first.first
-  ]
-]
-
-scenario parse-nested-list-2 [
-  local-scope
-  s:text <- new [((abc) def)]
-  x:address:cell <- parse s
-  trace-should-contain [
-    app/parse: < < abc | <> > | < def | <> > >
-  ]
-  10:boolean/raw <- is-pair? x
-  x1:address:cell <- first x
-  11:boolean/raw <- is-pair? x
-  x2:address:cell <- first x1
-  s1:text, 12:boolean/raw <- maybe-convert *x2, atom:variant
-  13:address:cell/raw <- rest x1
-  x3:address:cell <- rest x
-  x4:address:cell <- first x3
-  s2:text, 14:boolean/raw <- maybe-convert *x4, atom:variant
-  15:address:cell/raw <- rest x3
-  20:array:character/raw <- copy *s1
-  30:array:character/raw <- copy *s2
-  memory-should-contain [
-    10 <- 1  # parse result is a pair
-    11 <- 1  # result.first is a pair
-    12 <- 1  # result.first.first is an atom
-    13 <- 0  # result.first.rest is nil
-    14 <- 1  # result.rest.first is an atom
-    15 <- 0  # result.rest.rest is nil
-    20:array:character <- [abc]  # result.first.first
-    30:array:character <- [def]  # result.rest.first
-  ]
-]
-
-# todo: uncomment these tests after we figure out how to continue tests after
-# assertion failures
-#? scenario parse-error [
-#?   local-scope
-#?   s:text <- new [(]
-#? #?   hide-errors
-#?   x:address:cell <- parse s
-#? #?   show-errors
-#?   trace-should-contain [
-#?     error: unbalanced '(' in expression
-#?   ]
-#? ]
-#? 
-#? scenario parse-error-after-element [
-#?   local-scope
-#?   s:text <- new [(abc]
-#? #?   hide-errors
-#?   x:address:cell <- parse s
-#? #?   show-errors
-#?   trace-should-contain [
-#?     error: unbalanced '(' in expression
-#?   ]
-#? ]
-
-scenario parse-dotted-list-of-two-atoms [
-  local-scope
-  s:text <- new [(abc . def)]
-  x:address:cell <- parse s
-  trace-should-contain [
-    app/parse: < abc | def >
-  ]
-  10:boolean/raw <- is-pair? x
-  x1:address:cell <- first x
-  x2:address:cell <- rest x
-  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
-  s2:text, 12:boolean/raw <- maybe-convert *x2, atom:variant
-  20:array:character/raw <- copy *s1
-  30:array:character/raw <- copy *s2
-  memory-should-contain [
-    # parses to < abc | def >
-    10 <- 1  # parse result is a pair
-    11 <- 1  # result.first is an atom
-    12 <- 1  # result.rest is an atom
-    20:array:character <- [abc]  # result.first
-    30:array:character <- [def]  # result.rest
-  ]
-]
-
-scenario parse-dotted-list-of-more-than-two-atoms [
-  local-scope
-  s:text <- new [(abc def . ghi)]
-  x:address:cell <- parse s
-  trace-should-contain [
-    app/parse: < abc | < def | ghi > >
-  ]
-  10:boolean/raw <- is-pair? x
-  x1:address:cell <- first x
-  x2:address:cell <- rest x
-  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
-  12:boolean/raw <- is-pair? x2
-  x3:address:cell <- first x2
-  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
-  x4:address:cell <- rest x2
-  s3:text, 14:boolean/raw <- maybe-convert *x4, atom:variant
-  20:array:character/raw <- copy *s1
-  30:array:character/raw <- copy *s2
-  40:array:character/raw <- copy *s3
-  memory-should-contain [
-    10 <- 1  # parse result is a pair
-    11 <- 1  # result.first is an atom
-    12 <- 1  # result.rest is a pair
-    13 <- 1  # result.rest.first is an atom
-    14 <- 1  # result.rest.rest is an atom
-    20:array:character <- [abc]  # result.first
-    30:array:character <- [def]  # result.rest.first
-    40:array:character <- [ghi]  # result.rest.rest
-  ]
-]
-
-## convert tree of cells to mu text
-
-def to-mu in:address:cell -> out:address:array:character [
-  local-scope
-  load-ingredients
-  buf:address:buffer <- new-buffer 30
-  buf <- to-mu in, buf
-  out <- buffer-to-array buf
-]
-
-def to-mu in:address:cell, buf:address:buffer -> buf:address:buffer, result-name:address:array:character [
-  local-scope
-  load-ingredients
-  # null cell? no change.
-  # pair with all atoms? gensym a new variable
-  # pair containing other pairs? recurse
-  result-name <- copy 0
-]
diff --git a/lambda_to_mu.mu b/lambda_to_mu.mu
new file mode 100644
index 00000000..ed3cd72c
--- /dev/null
+++ b/lambda_to_mu.mu
@@ -0,0 +1,584 @@
+## experimental compiler to translate programs written in a generic
+## expression-oriented language called 'lambda' into mu
+
+scenario convert-lambda [
+  run [
+    local-scope
+    1:text/raw <- lambda-to-mu [(add a (multiply b c))]
+    2:array:character/raw <- copy *1:text/raw
+  ]
+  memory-should-contain [
+    2:array:character <- [t1 <- multiply b c
+result <- add a t1]
+  ]
+]
+
+def lambda-to-mu in:address:array:character -> out:address:array:character [
+  local-scope
+  load-ingredients
+  out <- copy 0
+  cells:address:cell <- parse in
+  out <- to-mu cells
+]
+
+# 'parse' will turn lambda expressions into trees made of cells
+exclusive-container cell [
+  atom:text
+  pair:pair
+]
+
+# printed below as < first | rest >
+container pair [
+  first:address:cell
+  rest:address:cell
+]
+
+def new-atom name:address:array:character -> result:address:cell [
+  local-scope
+  load-ingredients
+  result <- new cell:type
+  *result <- merge 0/tag:atom, name
+]
+
+def new-pair a:address:cell, b:address:cell -> result:address:cell [
+  local-scope
+  load-ingredients
+  result <- new cell:type
+  *result <- merge 1/tag:pair, a/first, b/rest
+]
+
+def is-atom? x:address:cell -> result:boolean [
+  local-scope
+  load-ingredients
+  reply-unless x, 0/false
+  _, result <- maybe-convert *x, atom:variant
+]
+
+def is-pair? x:address:cell -> result:boolean [
+  local-scope
+  load-ingredients
+  reply-unless x, 0/false
+  _, result <- maybe-convert *x, pair:variant
+]
+
+scenario atom-is-not-pair [
+  local-scope
+  s:text <- new [a]
+  x:address:cell <- new-atom s
+  10:boolean/raw <- is-atom? x
+  11:boolean/raw <- is-pair? x
+  memory-should-contain [
+    10 <- 1
+    11 <- 0
+  ]
+]
+
+scenario pair-is-not-atom [
+  local-scope
+  # construct (a . nil)
+  s:text <- new [a]
+  x:address:cell <- new-atom s
+  y:address:cell <- new-pair x, 0/nil
+  10:boolean/raw <- is-atom? y
+  11:boolean/raw <- is-pair? y
+  memory-should-contain [
+    10 <- 0
+    11 <- 1
+  ]
+]
+
+def atom-match? x:address:cell, pat:address:array:character -> result:boolean [
+  local-scope
+  load-ingredients
+  s:text, is-atom?:boolean <- maybe-convert *x, atom:variant
+  reply-unless is-atom?, 0/false
+  result <- equal pat, s
+]
+
+scenario atom-match [
+  local-scope
+  x:address:cell <- new-atom [abc]
+  10:boolean/raw <- atom-match? x, [abc]
+  memory-should-contain [
+    10 <- 1
+  ]
+]
+
+def first x:address:cell -> result:address:cell [
+  local-scope
+  load-ingredients
+  pair:pair, pair?:boolean <- maybe-convert *x, pair:variant
+  reply-unless pair?, 0/nil
+  result <- get pair, first:offset
+]
+
+def rest x:address:cell -> result:address:cell [
+  local-scope
+  load-ingredients
+  pair:pair, pair?:boolean <- maybe-convert *x, pair:variant
+  reply-unless pair?, 0/nil
+  result <- get pair, rest:offset
+]
+
+def set-first base:address:cell, new-first:address:cell -> base:address:cell [
+  local-scope
+  load-ingredients
+  pair:pair, is-pair?:boolean <- maybe-convert *base, pair:variant
+  reply-unless is-pair?
+  pair <- put pair, first:offset, new-first
+  *base <- merge 1/pair, pair
+]
+
+def set-rest base:address:cell, new-rest:address:cell -> base:address:cell [
+  local-scope
+  load-ingredients
+  pair:pair, is-pair?:boolean <- maybe-convert *base, pair:variant
+  reply-unless is-pair?
+  pair <- put pair, rest:offset, new-rest
+  *base <- merge 1/pair, pair
+]
+
+scenario cell-operations-on-atom [
+  local-scope
+  s:text <- new [a]
+  x:address:cell <- new-atom s
+  10:address:cell/raw <- first x
+  11:address:cell/raw <- rest x
+  memory-should-contain [
+    10 <- 0  # first is nil
+    11 <- 0  # rest is nil
+  ]
+]
+
+scenario cell-operations-on-pair [
+  local-scope
+  # construct (a . nil)
+  s:text <- new [a]
+  x:address:cell <- new-atom s
+  y:address:cell <- new-pair x, 0/nil
+  x2:address:cell <- first y
+  10:boolean/raw <- equal x, x2
+  11:address:cell/raw <- rest y
+  memory-should-contain [
+    10 <- 1  # first is correct
+    11 <- 0  # rest is nil
+  ]
+]
+
+## convert lambda text to a tree of cells
+
+def parse in:address:array:character -> out:address:cell [
+  local-scope
+  load-ingredients
+  s:address:stream:character <- new-stream in
+  out, s <- parse s
+  trace 2, [app/parse], out
+]
+
+def parse in:address:stream:character -> out:address:cell, in:address:stream:character [
+  local-scope
+  load-ingredients
+  # skip whitespace
+  in <- skip-whitespace in
+  c:character, eof?:boolean <- peek in
+  reply-if eof?, 0/nil
+  pair?:boolean <- equal c, 40/open-paren
+  {
+    break-if pair?
+    # atom
+    b:address:buffer <- new-buffer 30
+    {
+      done?:boolean <- end-of-stream? in
+      break-if done?
+      # stop before close paren or space
+      c:character <- peek in
+      done? <- equal c, 41/close-paren
+      break-if done?
+      done? <- space? c
+      break-if done?
+      c <- read in
+      b <- append b, c
+      loop
+    }
+    s:text <- buffer-to-array b
+    out <- new-atom s
+  }
+  {
+    break-unless pair?
+    # pair
+    read in  # skip the open-paren
+    out <- new cell:type  # start out with nil
+    # read in first element of pair
+    {
+      end?:boolean <- end-of-stream? in
+      not-end?:boolean <- not end?
+      assert not-end?, [unbalanced '(' in expression]
+      c <- peek in
+      close-paren?:boolean <- equal c, 41/close-paren
+      break-if close-paren?
+      first:address:cell, in <- parse in
+      *out <- merge 1/pair, first, 0/nil
+    }
+    # read in any remaining elements
+    curr:address:cell <- copy out
+    {
+      in <- skip-whitespace in
+      end?:boolean <- end-of-stream? in
+      not-end?:boolean <- not end?
+      assert not-end?, [unbalanced '(' in expression]
+      # termination check: ')'
+      c <- peek in
+      {
+        close-paren?:boolean <- equal c, 41/close-paren
+        break-unless close-paren?
+        read in  # skip ')'
+        break +end-pair:label
+      }
+      # still here? read next element of pair
+      next:address:cell, in <- parse in
+      is-dot?:boolean <- atom-match? next, [.]
+      {
+        break-if is-dot?
+        next-curr:address:cell <- new-pair next, 0/nil
+        curr <- set-rest curr, next-curr
+        curr <- rest curr
+      }
+      {
+        break-unless is-dot?
+        # deal with dotted pair
+        in <- skip-whitespace in
+        c <- peek in
+        not-close-paren?:boolean <- not-equal c, 41/close-paren
+        assert not-close-paren?, [')' cannot immediately follow '.']
+        final:address:cell <- parse in
+        curr <- set-rest curr, final
+        # we're not gonna update curr, so better make sure the next iteration
+        # is going to end the pair
+        in <- skip-whitespace in
+        c <- peek in
+        close-paren?:boolean <- equal c, 41/close-paren
+        assert close-paren?, ['.' must be followed by exactly one expression before ')']
+      }
+      loop
+    }
+    +end-pair
+  }
+]
+
+def skip-whitespace in:address:stream:character -> in:address:stream:character [
+  local-scope
+  load-ingredients
+  {
+    done?:boolean <- end-of-stream? in
+    reply-if done?, 0/null
+    c:character <- peek in
+    space?:boolean <- space? c
+    break-unless space?
+    read in  # skip
+    loop
+  }
+]
+
+def to-text x:address:cell -> out:address:array:character [
+  local-scope
+  load-ingredients
+  buf:address:buffer <- new-buffer 30
+  buf <- to-buffer x, buf
+  out <- buffer-to-array buf
+]
+
+def to-buffer x:address:cell, buf:address:buffer -> buf:address:buffer [
+  local-scope
+  load-ingredients
+  # base case: empty cell
+  {
+    break-if x
+    buf <- append buf, [<>]
+    reply
+  }
+  # base case: atom
+  {
+    s:text, atom?:boolean <- maybe-convert *x, atom:variant
+    break-unless atom?
+    buf <- append buf, s
+    reply
+  }
+  # recursive case: pair
+  buf <- append buf, [< ]
+  first:address:cell <- first x
+  buf <- to-buffer first, buf
+  buf <- append buf, [ | ]
+  rest:address:cell <- rest x
+  buf <- to-buffer rest, buf
+  buf <- append buf, [ >]
+]
+
+scenario parse-single-letter-atom [
+  local-scope
+  s:text <- new [a]
+  x:address:cell <- parse s
+  s2:text, 10:boolean/raw <- maybe-convert *x, atom:variant
+  11:array:character/raw <- copy *s2
+  memory-should-contain [
+    10 <- 1  # parse result is an atom
+    11:array:character <- [a]
+  ]
+]
+
+scenario parse-atom [
+  local-scope
+  s:text <- new [abc]
+  x:address:cell <- parse s
+  s2:text, 10:boolean/raw <- maybe-convert *x, atom:variant
+  11:array:character/raw <- copy *s2
+  memory-should-contain [
+    10 <- 1  # parse result is an atom
+    11:array:character <- [abc]
+  ]
+]
+
+scenario parse-list-of-two-atoms [
+  local-scope
+  s:text <- new [(abc def)]
+  x:address:cell <- parse s
+  trace-should-contain [
+    app/parse: < abc | < def | <> > >
+  ]
+  10:boolean/raw <- is-pair? x
+  x1:address:cell <- first x
+  x2:address:cell <- rest x
+  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
+  12:boolean/raw <- is-pair? x2
+  x3:address:cell <- first x2
+  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
+  14:address:cell/raw <- rest x2
+  20:array:character/raw <- copy *s1
+  30:array:character/raw <- copy *s2
+  memory-should-contain [
+    10 <- 1  # parse result is a pair
+    11 <- 1  # result.first is an atom
+    12 <- 1  # result.rest is a pair
+    13 <- 1  # result.rest.first is an atom
+    14 <- 0  # result.rest.rest is nil
+    20:array:character <- [abc]  # result.first
+    30:array:character <- [def]  # result.rest.first
+  ]
+]
+
+scenario parse-list-with-extra-spaces [
+  local-scope
+  s:text <- new [ ( abc  def ) ]  # extra spaces
+  x:address:cell <- parse s
+  trace-should-contain [
+    app/parse: < abc | < def | <> > >
+  ]
+  10:boolean/raw <- is-pair? x
+  x1:address:cell <- first x
+  x2:address:cell <- rest x
+  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
+  12:boolean/raw <- is-pair? x2
+  x3:address:cell <- first x2
+  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
+  14:address:cell/raw <- rest x2
+  20:array:character/raw <- copy *s1
+  30:array:character/raw <- copy *s2
+  memory-should-contain [
+    10 <- 1  # parse result is a pair
+    11 <- 1  # result.first is an atom
+    12 <- 1  # result.rest is a pair
+    13 <- 1  # result.rest.first is an atom
+    14 <- 0  # result.rest.rest is nil
+    20:array:character <- [abc]  # result.first
+    30:array:character <- [def]  # result.rest.first
+  ]
+]
+
+scenario parse-list-of-more-than-two-atoms [
+  local-scope
+  s:text <- new [(abc def ghi)]
+  x:address:cell <- parse s
+  trace-should-contain [
+    app/parse: < abc | < def | < ghi | <> > > >
+  ]
+  10:boolean/raw <- is-pair? x
+  x1:address:cell <- first x
+  x2:address:cell <- rest x
+  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
+  12:boolean/raw <- is-pair? x2
+  x3:address:cell <- first x2
+  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
+  x4:address:cell <- rest x2
+  14:boolean/raw <- is-pair? x4
+  x5:address:cell <- first x4
+  s3:text, 15:boolean/raw <- maybe-convert *x5, atom:variant
+  16:address:cell/raw <- rest x4
+  20:array:character/raw <- copy *s1
+  30:array:character/raw <- copy *s2
+  40:array:character/raw <- copy *s3
+  memory-should-contain [
+    10 <- 1  # parse result is a pair
+    11 <- 1  # result.first is an atom
+    12 <- 1  # result.rest is a pair
+    13 <- 1  # result.rest.first is an atom
+    14 <- 1  # result.rest.rest is a pair
+    15 <- 1  # result.rest.rest.first is an atom
+    16 <- 0  # result.rest.rest.rest is nil
+    20:array:character <- [abc]  # result.first
+    30:array:character <- [def]  # result.rest.first
+    40:array:character <- [ghi]  # result.rest.rest
+  ]
+]
+
+scenario parse-nested-list [
+  local-scope
+  s:text <- new [((abc))]
+  x:address:cell <- parse s
+  trace-should-contain [
+    app/parse: < < abc | <> > | <> >
+  ]
+  10:boolean/raw <- is-pair? x
+  x1:address:cell <- first x
+  11:boolean/raw <- is-pair? x
+  x2:address:cell <- first x1
+  s1:text, 12:boolean/raw <- maybe-convert *x2, atom:variant
+  13:address:cell/raw <- rest x1
+  14:address:cell/raw <- rest x
+  20:array:character/raw <- copy *s1
+  memory-should-contain [
+    10 <- 1  # parse result is a pair
+    11 <- 1  # result.first is a pair
+    12 <- 1  # result.first.first is an atom
+    13 <- 0  # result.first.rest is nil
+    14 <- 0  # result.rest is nil
+    20:array:character <- [abc]  # result.first.first
+  ]
+]
+
+scenario parse-nested-list-2 [
+  local-scope
+  s:text <- new [((abc) def)]
+  x:address:cell <- parse s
+  trace-should-contain [
+    app/parse: < < abc | <> > | < def | <> > >
+  ]
+  10:boolean/raw <- is-pair? x
+  x1:address:cell <- first x
+  11:boolean/raw <- is-pair? x
+  x2:address:cell <- first x1
+  s1:text, 12:boolean/raw <- maybe-convert *x2, atom:variant
+  13:address:cell/raw <- rest x1
+  x3:address:cell <- rest x
+  x4:address:cell <- first x3
+  s2:text, 14:boolean/raw <- maybe-convert *x4, atom:variant
+  15:address:cell/raw <- rest x3
+  20:array:character/raw <- copy *s1
+  30:array:character/raw <- copy *s2
+  memory-should-contain [
+    10 <- 1  # parse result is a pair
+    11 <- 1  # result.first is a pair
+    12 <- 1  # result.first.first is an atom
+    13 <- 0  # result.first.rest is nil
+    14 <- 1  # result.rest.first is an atom
+    15 <- 0  # result.rest.rest is nil
+    20:array:character <- [abc]  # result.first.first
+    30:array:character <- [def]  # result.rest.first
+  ]
+]
+
+# todo: uncomment these tests after we figure out how to continue tests after
+# assertion failures
+#? scenario parse-error [
+#?   local-scope
+#?   s:text <- new [(]
+#? #?   hide-errors
+#?   x:address:cell <- parse s
+#? #?   show-errors
+#?   trace-should-contain [
+#?     error: unbalanced '(' in expression
+#?   ]
+#? ]
+#? 
+#? scenario parse-error-after-element [
+#?   local-scope
+#?   s:text <- new [(abc]
+#? #?   hide-errors
+#?   x:address:cell <- parse s
+#? #?   show-errors
+#?   trace-should-contain [
+#?     error: unbalanced '(' in expression
+#?   ]
+#? ]
+
+scenario parse-dotted-list-of-two-atoms [
+  local-scope
+  s:text <- new [(abc . def)]
+  x:address:cell <- parse s
+  trace-should-contain [
+    app/parse: < abc | def >
+  ]
+  10:boolean/raw <- is-pair? x
+  x1:address:cell <- first x
+  x2:address:cell <- rest x
+  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
+  s2:text, 12:boolean/raw <- maybe-convert *x2, atom:variant
+  20:array:character/raw <- copy *s1
+  30:array:character/raw <- copy *s2
+  memory-should-contain [
+    # parses to < abc | def >
+    10 <- 1  # parse result is a pair
+    11 <- 1  # result.first is an atom
+    12 <- 1  # result.rest is an atom
+    20:array:character <- [abc]  # result.first
+    30:array:character <- [def]  # result.rest
+  ]
+]
+
+scenario parse-dotted-list-of-more-than-two-atoms [
+  local-scope
+  s:text <- new [(abc def . ghi)]
+  x:address:cell <- parse s
+  trace-should-contain [
+    app/parse: < abc | < def | ghi > >
+  ]
+  10:boolean/raw <- is-pair? x
+  x1:address:cell <- first x
+  x2:address:cell <- rest x
+  s1:text, 11:boolean/raw <- maybe-convert *x1, atom:variant
+  12:boolean/raw <- is-pair? x2
+  x3:address:cell <- first x2
+  s2:text, 13:boolean/raw <- maybe-convert *x3, atom:variant
+  x4:address:cell <- rest x2
+  s3:text, 14:boolean/raw <- maybe-convert *x4, atom:variant
+  20:array:character/raw <- copy *s1
+  30:array:character/raw <- copy *s2
+  40:array:character/raw <- copy *s3
+  memory-should-contain [
+    10 <- 1  # parse result is a pair
+    11 <- 1  # result.first is an atom
+    12 <- 1  # result.rest is a pair
+    13 <- 1  # result.rest.first is an atom
+    14 <- 1  # result.rest.rest is an atom
+    20:array:character <- [abc]  # result.first
+    30:array:character <- [def]  # result.rest.first
+    40:array:character <- [ghi]  # result.rest.rest
+  ]
+]
+
+## convert tree of cells to mu text
+
+def to-mu in:address:cell -> out:address:array:character [
+  local-scope
+  load-ingredients
+  buf:address:buffer <- new-buffer 30
+  buf <- to-mu in, buf
+  out <- buffer-to-array buf
+]
+
+def to-mu in:address:cell, buf:address:buffer -> buf:address:buffer, result-name:address:array:character [
+  local-scope
+  load-ingredients
+  # null cell? no change.
+  # pair with all atoms? gensym a new variable
+  # pair containing other pairs? recurse
+  result-name <- copy 0
+]
diff --git a/real-files.mu b/real-files.mu
deleted file mode 100644
index 50137a0b..00000000
--- a/real-files.mu
+++ /dev/null
@@ -1,18 +0,0 @@
-# example program: read a character from one file and write it to another
-# BEWARE: this will modify your file system
-# before running it, put a character into /tmp/mu-x
-# after running it, check /tmp/mu-y
-
-def main [
-  local-scope
-  f:number/file <- $open-file-for-reading [/tmp/mu-x]
-  $print [file to read from: ], f, 10/newline
-  c:character, eof?:boolean <- $read-from-file f
-  $print [copying ], c, 10/newline
-  f <- $close-file f
-  $print [file after closing: ], f, 10/newline
-  f <- $open-file-for-writing [/tmp/mu-y]
-  $print [file to write to: ], f, 10/newline
-  $write-to-file f, c
-  f <- $close-file f
-]
diff --git a/real_files.mu b/real_files.mu
new file mode 100644
index 00000000..50137a0b
--- /dev/null
+++ b/real_files.mu
@@ -0,0 +1,18 @@
+# example program: read a character from one file and write it to another
+# BEWARE: this will modify your file system
+# before running it, put a character into /tmp/mu-x
+# after running it, check /tmp/mu-y
+
+def main [
+  local-scope
+  f:number/file <- $open-file-for-reading [/tmp/mu-x]
+  $print [file to read from: ], f, 10/newline
+  c:character, eof?:boolean <- $read-from-file f
+  $print [copying ], c, 10/newline
+  f <- $close-file f
+  $print [file after closing: ], f, 10/newline
+  f <- $open-file-for-writing [/tmp/mu-y]
+  $print [file to write to: ], f, 10/newline
+  $write-to-file f, c
+  f <- $close-file f
+]
-- 
cgit 1.4.1-2-gfad0