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refactor(debug): convert pretty-print helpers to Repr methods #3284

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Merged
bobzhang merged 1 commit into from
Apr 8, 2026
Merged

refactor(debug): convert pretty-print helpers to Repr methods #3284

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19 changes: 11 additions & 8 deletions debug/delta.mbt
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Original file line number Diff line number Diff line change
Expand Up @@ -194,9 +194,12 @@ fn prune_delta(max_depth : Int?, delta : ReprDelta) -> ReprDelta {
Same(label, children.map(child => go(next_depth, child)))
}
Different(left, right) =>
Different(prune_info(left, depth=d), prune_info(right, depth=d))
Extra1(x) => Extra1(prune_info(x, depth=d))
Extra2(x) => Extra2(prune_info(x, depth=d))
Different(
left.prune_info(max_depth=Some(d)),
right.prune_info(max_depth=Some(d)),
)
Extra1(x) => Extra1(x.prune_info(max_depth=Some(d)))
Extra2(x) => Extra2(x.prune_info(max_depth=Some(d)))
}
}
}
Expand Down Expand Up @@ -259,13 +262,13 @@ fn render_delta(threshold : Int, use_ansi : Bool, delta : ReprDelta) -> Content
with_resizing(
delta_root_size(delta),
threshold,
pretty_print_repr_go(label, children),
label.pretty_print(children),
)
}
Different(left, right) => {
let children : Array[Content] = [
render_repr(threshold, left),
render_repr(threshold, right),
left.render_repr(threshold),
right.render_repr(threshold),
]
with_resizing(
0,
Expand All @@ -281,7 +284,7 @@ fn render_delta(threshold : Int, use_ansi : Bool, delta : ReprDelta) -> Content
)
}
Extra1(x) => {
let children : Array[Content] = [render_repr(threshold, x)]
let children : Array[Content] = [x.render_repr(threshold)]
with_resizing(
0,
threshold,
Expand All @@ -292,7 +295,7 @@ fn render_delta(threshold : Int, use_ansi : Bool, delta : ReprDelta) -> Content
)
}
Extra2(x) => {
let children : Array[Content] = [render_repr(threshold, x)]
let children : Array[Content] = [x.render_repr(threshold)]
with_resizing(
0,
threshold,
Expand Down
118 changes: 47 additions & 71 deletions debug/pretty_print.mbt
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,19 +23,12 @@ let default_max_depth : Int = 16
let default_threshold : Int = 70

///|
/// Prune a `Repr` using max_depth (replacing with `Omitted`).
fn prune_repr_info(max_depth : Int?, info : Repr) -> Repr {
match max_depth {
None => info
Some(depth) => prune_info(info, depth~)
}
}

///|
/// Prune a `Repr` tree to a given depth (replacing pruned subtrees).
/// Prune a `Repr` tree to a given depth (replacing pruned subtrees with
/// `Repr::omitted()`). Returns `self` unchanged when `max_depth` is `None`.
///
/// Parameters:
/// - `depth~`: maximum depth. Values `<= 0` are treated as `1`.
/// - `max_depth~`: optional maximum depth. `None` means no pruning.
/// Values `<= 0` are treated as `1`.
/// - `replacement?`: the node used to replace pruned subtrees.
/// Defaults to `Repr::omitted()`.
///
Expand All @@ -44,30 +37,35 @@ fn prune_repr_info(max_depth : Int?, info : Repr) -> Repr {
/// - When the depth budget is exhausted and the node has children:
/// - if `info_adds_depth() == false`, pruning continues into its children;
/// - otherwise the whole subtree is replaced by `replacement`.
fn prune_info(
info : Repr,
fn Repr::prune_info(
self : Repr,
replacement? : Repr = Repr::omitted(),
depth~ : Int,
max_depth~ : Int?,
) -> Repr {
fn go(d : Int, node : Repr) -> Repr {
let children = node.children()
if d <= 0 {
if children.is_empty() {
node
} else if !node.info_adds_depth() {
node.with_children(children.map(child => go(d, child)))
} else {
replacement
match max_depth {
None => self
Some(depth) => {
fn go(d : Int, node : Repr) -> Repr {
let children = node.children()
if d <= 0 {
if children.is_empty() {
node
} else if !node.info_adds_depth() {
node.with_children(children.map(child => go(d, child)))
} else {
replacement
}
} else if children.is_empty() {
node
} else {
let next_depth = if node.info_adds_depth() { d - 1 } else { d }
node.with_children(children.map(child => go(next_depth, child)))
}
}
} else if children.is_empty() {
node
} else {
let next_depth = if node.info_adds_depth() { d - 1 } else { d }
node.with_children(children.map(child => go(next_depth, child)))

go(Int::max(1, depth), self)
}
}

go(Int::max(1, depth), info)
}

///|
Expand Down Expand Up @@ -118,31 +116,23 @@ fn is_unquoted_key(key : String) -> Bool {
})
}

///|
/// Escape a string as a literal (used for quoted keys and `String` values).
fn quote_string_literal(s : String) -> String {
s.escape()
}

///|
/// Pretty-print a record field name (quoted when needed).
fn pretty_print_label(name : String) -> String {
if is_unquoted_key(name) {
name
} else {
quote_string_literal(name)
name.escape()
}
}

///|
/// Render a single `Repr` node (label + rendered children) into `Content`.
fn pretty_print_repr_go(label : Repr, children : Array[Content]) -> Content {
match label {
fn Repr::pretty_print(self : Repr, children : Array[Content]) -> Content {
match self {
UnitLit => comma_seq("(", ")", [])
Integer(s) => {
let needs_parens = s.length() > 0 && s.code_unit_at(0) == '-'
no_parens(content_parens(if needs_parens { 1 } else { 0 }, [s]))
}
Integer(s) =>
no_parens(content_parens(if s is ['-', ..] { 1 } else { 0 }, [s]))
DoubleLit(x) => {
let needs_parens = 1.0 / x < 0.0
leaf(x.to_string(), needs_parens~)
Expand All @@ -153,7 +143,7 @@ fn pretty_print_repr_go(label : Repr, children : Array[Content]) -> Content {
}
BoolLit(x) => leaf(x.to_string())
CharLit(x) => leaf(x.escape())
StringLit(x) => no_parens(verbatim(quote_string_literal(x)))
StringLit(x) => no_parens(verbatim(x.escape()))
Tuple(_) => comma_seq("(", ")", children.map(x => x.no_wrap()))
Enum(name, _) =>
match children {
Expand Down Expand Up @@ -193,13 +183,9 @@ fn pretty_print_repr_go(label : Repr, children : Array[Content]) -> Content {
print_content(surround("", ": ", k)) + one,
]),
)
[first, ..] => {
let n = v.lines.length()
let rest = if n <= 1 { [] } else { v.lines[1:n].to_array() }
// put the key and the first line of value on the same line
// then keep the remaining lines of the value as-is.
[first, .. rest] => {
let head = print_content(surround("", ": ", k)) + first
no_parens(content_parens(1 + k.size + v.size, [head] + rest))
no_parens(content_parens(1 + k.size + v.size, [head, ..rest]))
}
}
}
Expand All @@ -212,13 +198,10 @@ fn pretty_print_repr_go(label : Repr, children : Array[Content]) -> Content {
[] => empty_content()
[first] =>
no_parens(content_parens(1 + val.size, [name + "=" + first]))
[first, ..] => {
let n = val.lines.length()
let rest = if n <= 1 { [] } else { val.lines[1:n].to_array() }
[first, .. rest] =>
no_parens(
content_parens(1 + val.size, [name + "=" + first] + rest),
content_parens(1 + val.size, [name + "=" + first, ..rest]),
)
}
}
_ => empty_content()
}
Expand All @@ -230,13 +213,10 @@ fn pretty_print_repr_go(label : Repr, children : Array[Content]) -> Content {
match v.lines {
[] => empty_content()
[one] => no_parens(content_parens(1 + v.size, [label + ": " + one]))
[first, ..] => {
let n = v.lines.length()
let rest = if n <= 1 { [] } else { v.lines[1:n].to_array() }
[first, .. rest] =>
no_parens(
content_parens(1 + v.size, [label + ": " + first] + rest),
content_parens(1 + v.size, [label + ": " + first, ..rest]),
)
}
}
}
_ => empty_content()
Expand All @@ -247,14 +227,10 @@ fn pretty_print_repr_go(label : Repr, children : Array[Content]) -> Content {

///|
/// Render a `Repr` as `Content` with resizing decisions.
fn render_repr(threshold : Int, info : Repr) -> Content {
let label = info.shallow()
let children = info.children().map(child => render_repr(threshold, child))
with_resizing(
info_size(label),
threshold,
pretty_print_repr_go(label, children),
)
fn Repr::render_repr(self : Repr, threshold : Int) -> Content {
let label = self.shallow()
let children = self.children().map(child => child.render_repr(threshold))
with_resizing(info_size(label), threshold, label.pretty_print(children))
}

///|
Expand All @@ -264,7 +240,7 @@ fn render_repr(threshold : Int, info : Repr) -> Content {
/// - `max_depth?`: maximum expansion depth; deeper subtrees are replaced with `...`.
/// Defaults to `4` when `None`. Values `<= 0` are treated as `1`.
/// - `compact_threshold?`: compact-vs-multiline layout threshold.
/// The printer uses a heuristic “size” for nodes; when the structure is deemed
/// The printer uses a heuristic "size" for nodes; when the structure is deemed
/// small enough under this threshold, it is kept on one line, otherwise it is
/// broken into multiple lines.
/// Larger values prefer single-line output. Defaults to `80` when `None`.
Expand All @@ -274,8 +250,8 @@ pub fn render(r : Repr, max_depth? : Int) -> String {
None => Some(default_max_depth)
}
let threshold = default_threshold
let info = prune_repr_info(max_depth, r)
print_content(render_repr(threshold, info).no_wrap())
let info = r.prune_info(max_depth~)
print_content(info.render_repr(threshold).no_wrap())
}

///|
Expand Down
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