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fn parse-input tokens: (addr stream cell), out: (addr handle cell), trace: (addr trace) {
rewind-stream tokens
var empty?/eax: boolean <- stream-empty? tokens
compare empty?, 0/false
{
break-if-=
error trace, "nothing to parse"
return
}
var close-paren?/eax: boolean <- parse-sexpression tokens, out, trace
{
compare close-paren?, 0/false
break-if-=
error trace, "')' is not a valid expression"
return
}
{
var empty?/eax: boolean <- stream-empty? tokens
compare empty?, 0/false
break-if-!=
error trace, "unexpected tokens at end; only type in a single expression at a time"
}
}
# return value: true if close-paren was encountered
fn parse-sexpression tokens: (addr stream cell), _out: (addr handle cell), trace: (addr trace) -> _/eax: boolean {
trace-text trace, "read", "parse"
trace-lower trace
var curr-token-storage: cell
var curr-token/ecx: (addr cell) <- address curr-token-storage
var empty?/eax: boolean <- stream-empty? tokens
compare empty?, 0/false
{
break-if-=
error trace, "end of stream; never found a balancing ')'"
return 1/true
}
read-from-stream tokens, curr-token
$parse-sexpression:type-check: {
# not bracket -> parse atom
var bracket-token?/eax: boolean <- bracket-token? curr-token
compare bracket-token?, 0/false
{
break-if-!=
parse-atom curr-token, _out, trace
break $parse-sexpression:type-check
}
# open paren -> parse list
var open-paren?/eax: boolean <- open-paren-token? curr-token
compare open-paren?, 0/false
{
break-if-=
var curr/esi: (addr handle cell) <- copy _out
$parse-sexpression:list-loop: {
allocate-pair curr
var curr-addr/eax: (addr cell) <- lookup *curr
var left/ecx: (addr handle cell) <- get curr-addr, left
{
var close-paren?/eax: boolean <- parse-sexpression tokens, left, trace
compare close-paren?, 0/false
break-if-!= $parse-sexpression:list-loop
}
#
curr <- get curr-addr, right
loop
}
break $parse-sexpression:type-check
}
# close paren -> parse list
var close-paren?/eax: boolean <- close-paren-token? curr-token
compare close-paren?, 0/false
{
break-if-=
trace-higher trace
return 1/true
}
# otherwise abort
var stream-storage: (stream byte 0x40)
var stream/edx: (addr stream byte) <- address stream-storage
write stream, "unexpected token "
var curr-token-data-ah/eax: (addr handle stream byte) <- get curr-token, text-data
var curr-token-data/eax: (addr stream byte) <- lookup *curr-token-data-ah
rewind-stream curr-token-data
write-stream stream, curr-token-data
trace trace, "error", stream
}
trace-higher trace
return 0/false
}
fn parse-atom _curr-token: (addr cell), _out: (addr handle cell), trace: (addr trace) {
trace-text trace, "read", "parse atom"
var curr-token/ecx: (addr cell) <- copy _curr-token
var curr-token-data-ah/eax: (addr handle stream byte) <- get curr-token, text-data
var _curr-token-data/eax: (addr stream byte) <- lookup *curr-token-data-ah
var curr-token-data/esi: (addr stream byte) <- copy _curr-token-data
trace trace, "read", curr-token-data
# number
var number-token?/eax: boolean <- number-token? curr-token
compare number-token?, 0/false
{
break-if-=
rewind-stream curr-token-data
var _val/eax: int <- parse-decimal-int-from-stream curr-token-data
var val/ecx: int <- copy _val
var val-float/xmm0: float <- convert val
allocate-number _out
var out/eax: (addr handle cell) <- copy _out
var out-addr/eax: (addr cell) <- lookup *out
var dest/edi: (addr float) <- get out-addr, number-data
copy-to *dest, val-float
{
var stream-storage: (stream byte 0x40)
var stream/ecx: (addr stream byte) <- address stream-storage
write stream, "=> number "
print-number out-addr, stream, 0/no-trace
trace trace, "read", stream
}
return
}
# default: symbol
# just copy token data
allocate-symbol _out
var out/eax: (addr handle cell) <- copy _out
var out-addr/eax: (addr cell) <- lookup *out
var curr-token-data-ah/ecx: (addr handle stream byte) <- get curr-token, text-data
var dest-ah/edx: (addr handle stream byte) <- get out-addr, text-data
copy-object curr-token-data-ah, dest-ah
{
var stream-storage: (stream byte 0x40)
var stream/ecx: (addr stream byte) <- address stream-storage
write stream, "=> symbol "
print-symbol out-addr, stream, 0/no-trace
trace trace, "read", stream
}
}
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