## experimental compiler to translate programs written in a generic ## expression-oriented language called 'lambda' into Mu # incomplete; code generator not done # potential enhancements: # symbol table # poor man's macros # substitute one instruction with multiple, parameterized by inputs and products scenario convert-lambda [ run [ local-scope 1:text/raw <- lambda-to-mu [(add a (multiply b c))] 2:@:char/raw <- copy *1:text/raw ] memory-should-contain [ 2:array:character <- [t1 <- multiply b c result <- add a t1] ] ] def lambda-to-mu in:text -> out:text [ local-scope load-inputs out <- copy null cells:&: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:&:cell rest:&:cell ] def new-atom name:text -> result:&:cell [ local-scope load-inputs result <- new cell:type *result <- merge 0/tag:atom, name ] def new-pair a:&:cell, b:&:cell -> result:&:cell [ local-scope load-inputs result <- new cell:type *result <- merge 1/tag:pair, a/first, b/rest ] def is-atom? x:&:cell -> result:bool [ local-scope load-inputs return-unless x, false _, result <- maybe-convert *x, atom:variant ] def is-pair? x:&:cell -> result:bool [ local-scope load-inputs return-unless x, false _, result <- maybe-convert *x, pair:variant ] scenario atom-is-not-pair [ local-scope s:text <- new [a] x:&:cell <- new-atom s 10:bool/raw <- is-atom? x 11:bool/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:&:cell <- new-atom s y:&:cell <- new-pair x, null 10:bool/raw <- is-atom? y 11:bool/raw <- is-pair? y memory-should-contain [ 10 <- 0 11 <- 1 ] ] def atom-match? x:&:cell, pat:text -> result:bool [ local-scope load-inputs s:text, is-atom?:bool <- maybe-convert *x, atom:variant return-unless is-atom?, false result <- equal pat, s ] scenario atom-match [ local-scope x:&:cell <- new-atom [abc] 10:bool/raw <- atom-match? x, [abc] memory-should-contain [ 10 <- 1 ] ] def first x:&:cell -> result:&:cell [ local-scope load-inputs pair:pair, pair?:bool <- maybe-convert *x, pair:variant return-unless pair?, null result <- get pair, first:offset ] def rest x:&:cell -> result:&:cell [ local-scope load-inputs pair:pair, pair?:bool <- maybe-convert *x, pair:variant return-unless pair?, null result <- get pair, rest:offset ] def set-first base:&:cell, new-first:&:cell -> base:&:cell [ local-scope load-inputs pair:pair, is-pair?:bool <- maybe-convert *base, pair:variant return-unless is-pair? pair <- put pair, first:offset, new-first *base <- merge 1/pair, pair ] def set-rest base:&:cell, new-rest:&:cell -> base:&:cell [ local-scope load-inputs pair:pair, is-pair?:bool <- maybe-convert *base, pair:variant return-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:&:cell <- new-atom s 10:&:cell/raw <- first x 11:&: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:&:cell <- new-atom s y:&:cell <- new-pair x, null x2:&:cell <- first y 10:bool/raw <- equal x, x2 11:&: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:text -> out:&:cell [ local-scope load-inputs s:&:stream:char <- new-stream in out, s <- parse s trace 2, [app/parse], out ] def parse in:&:stream:char -> out:&:cell, in:&:stream:char [ local-scope load-inputs # skip whitespace in <- skip-whitespace in c:char, eof?:bool <- peek in return-if eof?, null pair?:bool <- equal c, 40/open-paren { break-if pair? # atom buf:&:buffer:char <- new-buffer 30 { done?:bool <- end-of-stream? in break-if done? # stop before close paren or space c:char <- peek in done? <- equal c, 41/close-paren break-if done? done? <- space? c break-if done? c <- read in buf <- append buf, c loop } s:text <- buffer-to-array buf 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?:bool <- end-of-stream? in not-end?:bool <- not end? assert not-end?, [unbalanced '(' in expression] c <- peek in close-paren?:bool <- equal c, 41/close-paren break-if close-paren? first:&:cell, in <- parse in *out <- merge 1/pair, first, null } # read in any remaining elements curr:&:cell <- copy out { in <- skip-whitespace in end?:bool <- end-of-stream? in not-end?:bool <- not end? assert not-end?, [unbalanced '(' in expression] # termination check: ')' c <- peek in { close-paren?:bool <- equal c, 41/close-paren break-unless close-paren? read in # skip ')' break +end-pair } # still here? read next element of pair next:&:cell, in <- parse in is-dot?:bool <- atom-match? next, [.] { break-if is-dot? next-curr:&:cell <- new-pair next, null 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?:bool <- not-equal c, 41/close-paren assert not-close-paren?, [')' cannot immediately follow '.'] final:&:cell <- parse in curr <- set-rest curr, final # we're not g
//: allow using literal strings anywhere that will accept immutable strings

void test_passing_literals_to_recipes() {
  run(
      "def main [\n"
      "  1:num/raw <- foo [abc]\n"
      "]\n"
      "def foo x:text -> n:num [\n"
      "  local-scope\n"
      "  load-ingredients\n"
      "  n <- length *x\n"
      "]\n"
  );
  CHECK_TRACE_CONTENTS(
      "mem: storing 3 in location 1\n"
  );
}

:(before "End Instruction Inserting/Deleting Transforms")
initialize_transform_rewrite_literal_string_to_text();
Transform.push_back(rewrite_literal_string_to_text);  // idempotent

:(before "End Globals")
set<string> recipes_taking_literal_strings;
:(code)
void initialize_transform_rewrite_literal_string_to_text() {
  recipes_taking_literal_strings.insert("assert");
  recipes_taking_literal_strings.insert("$print");
  recipes_taking_literal_strings.insert