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cgen: generate an unique sort comparator function for each .sort() call

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This commit is contained in:
Delyan Angelov 2020-11-25 13:41:05 +02:00
parent a46eda7c44
commit 35a0fe79f9
2 changed files with 59 additions and 38 deletions
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74
vlib/v/gen/cgen.v
View File

@ -4879,50 +4879,48 @@ fn (mut g Gen) gen_array_sort(node ast.CallExpr) {
verror('usage: .sort(a.field < b.field)')
}
// verror('sort(): unhandled type $typ $q.name')
compare_fn = 'compare_' + g.typ(typ)
tmp_name := g.new_tmp_var()
compare_fn = 'compare_${tmp_name}_' + g.typ(typ)
if is_reverse {
compare_fn += '_reverse'
}
if _ := g.table.find_fn(compare_fn) {
} else {
// Register a new custom `compare_xxx` function for qsort()
g.table.register_fn({
name: compare_fn
return_type: table.int_type
})
infix_expr := node.args[0].expr as ast.InfixExpr
styp := g.typ(typ)
// Variables `a` and `b` are used in the `.sort(a < b)` syntax, so we can reuse them
// when generating the function as long as the args are named the same.
g.definitions.writeln('int $compare_fn ($styp* a, $styp* b) {')
field_type := g.typ(infix_expr.left_type)
left_expr_str := g.write_expr_to_string(infix_expr.left).replace('.',
'->')
right_expr_str := g.write_expr_to_string(infix_expr.right).replace('.',
'->')
g.definitions.writeln('$field_type a_ = $left_expr_str;')
g.definitions.writeln('$field_type b_ = $right_expr_str;')
mut op1, mut op2 := '', ''
if infix_expr.left_type == table.string_type {
if is_reverse {
op1 = 'string_gt(a_, b_)'
op2 = 'string_lt(a_, b_)'
} else {
op1 = 'string_lt(a_, b_)'
op2 = 'string_gt(a_, b_)'
}
// Register a new custom `compare_xxx` function for qsort()
g.table.register_fn({
name: compare_fn
return_type: table.int_type
})
infix_expr := node.args[0].expr as ast.InfixExpr
styp := g.typ(typ)
// Variables `a` and `b` are used in the `.sort(a < b)` syntax, so we can reuse them
// when generating the function as long as the args are named the same.
g.definitions.writeln('int $compare_fn ($styp* a, $styp* b) {')
field_type := g.typ(infix_expr.left_type)
left_expr_str := g.write_expr_to_string(infix_expr.left).replace_once('.',
'->')
right_expr_str := g.write_expr_to_string(infix_expr.right).replace_once('.',
'->')
g.definitions.writeln('$field_type a_ = $left_expr_str;')
g.definitions.writeln('$field_type b_ = $right_expr_str;')
mut op1, mut op2 := '', ''
if infix_expr.left_type == table.string_type {
if is_reverse {
op1 = 'string_gt(a_, b_)'
op2 = 'string_lt(a_, b_)'
} else {
if is_reverse {
op1 = 'a_ > b_'
op2 = 'a_ < b_'
} else {
op1 = 'a_ < b_'
op2 = 'a_ > b_'
}
op1 = 'string_lt(a_, b_)'
op2 = 'string_gt(a_, b_)'
}
} else {
if is_reverse {
op1 = 'a_ > b_'
op2 = 'a_ < b_'
} else {
op1 = 'a_ < b_'
op2 = 'a_ > b_'
}
g.definitions.writeln('if ($op1) return -1;')
g.definitions.writeln('if ($op2) return 1; return 0; }\n')
}
g.definitions.writeln('if ($op1) return -1;')
g.definitions.writeln('if ($op2) return 1; return 0; }\n')
}
}
if is_reverse && !compare_fn.ends_with('_reverse') {

23
vlib/v/tests/sorting_by_different_criteria_test.v Normal file
View File

@ -0,0 +1,23 @@
struct Child {
f f64
}
struct Parent {
child Child
name string
}
fn test_sorting_by_different_criteria_in_same_function() {
mut arr := [
Parent{Child{0.2}, 'def'},
Parent{Child{0.1}, 'xyz'},
Parent{Child{0.3}, 'abc'},
]
assert arr[0].name == 'def'
arr.sort(a.name < b.name)
// println(arr)
assert arr[0].name == 'abc'
// println(arr)
arr.sort(a.child.f < b.child.f)
assert arr[0].name == 'xyz'
}