https://github.com/akkartik/mu/blob/main/shell/read.mu
 1 fn read-cell in: (addr gap-buffer), out: (addr handle cell), trace: (addr trace) {
 2   # eagerly tokenize everything so that the phases are easier to see in the trace
 3   var tokens-storage: (stream token 0x400)
 4   var tokens/edx: (addr stream token) <- address tokens-storage
 5   tokenize in, tokens, trace
 6   var error?/eax: boolean <- has-errors? trace
 7   compare error?, 0/false
 8   {
 9     break-if-=
10     return
11   }
12   # insert more parens based on indentation
13   var parenthesized-tokens-storage: (stream token 0x400)
14   var parenthesized-tokens/ecx: (addr stream token) <- address parenthesized-tokens-storage
15   parenthesize tokens, parenthesized-tokens, trace
16   var error?/eax: boolean <- has-errors? trace
17   compare error?, 0/false
18   {
19     break-if-=
20     return
21   }
22   parse-input parenthesized-tokens, out, trace
23   transform-infix out, trace
24 }