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fn macroexpand expr-ah: (addr handle cell), globals: (addr global-table), trace: (addr trace) {
# loop until convergence
var expanded?/eax: boolean <- macroexpand-iter expr-ah, globals, trace
compare expanded?, 0/false
loop-if-!=
}
# return true if we found any macros
fn macroexpand-iter _expr-ah: (addr handle cell), globals: (addr global-table), trace: (addr trace) -> _/eax: boolean {
# if car(expr) is a symbol defined as a macro, expand it
var expr-ah/esi: (addr handle cell) <- copy _expr-ah
var expr/eax: (addr cell) <- lookup *expr-ah
{
var expr-type/eax: (addr int) <- get expr, type
compare *expr-type, 0/pair
break-if-=
# not a pair
return 0/false
}
var first-ah/ebx: (addr handle cell) <- get expr, left
var rest-ah/ecx: (addr handle cell) <- get expr, right
var first/eax: (addr cell) <- lookup *first-ah
var definition-h: (handle cell)
var definition-ah/ebx: (addr handle cell) <- address definition-h
maybe-lookup-symbol-in-globals first, definition-ah, globals, trace
var definition/eax: (addr cell) <- lookup *definition-ah
compare definition, 0
{
break-if-!=
# no definition
return 0/false
}
{
var definition-type/eax: (addr int) <- get definition, type
compare *definition-type, 0/pair
break-if-=
# definition not a pair
return 0/false
}
{
var definition-car-ah/eax: (addr handle cell) <- get definition, left
var definition-car/eax: (addr cell) <- lookup *definition-car-ah
var macro?/eax: boolean <- litmac? definition-car
compare macro?, 0/false
break-if-!=
# definition not a macro
return 0/false
}
var macro-definition-ah/eax: (addr handle cell) <- get definition, right
# TODO: check car(macro-definition) is litfn
apply macro-definition-ah, rest-ah, expr-ah, globals, trace, 0/no-screen, 0/no-keyboard, 0/call-number
return 1/true
}
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