Struct Config 

pub struct Config<'a> { /* private fields */ }

Configuration for the diagnostic renderer

Implementations

impl<'a> Config<'a>

pub fn new() -> Self

Create a new config with default values.

pub fn with_cross_gap(self, enabled: bool) -> Self

Enable or disable cross gap rendering.

When enabled, vertical bars between labels are drawn with gaps for better visual clarity when labels overlap.

Default: depends on C library default

pub fn with_compact(self, enabled: bool) -> Self

Enable or disable compact mode.

In compact mode, the diagnostic output is more condensed:

• Underlines and arrows may be merged onto the same line
• Only meaningful label arrows are shown

Works with underlines enabled or disabled.

Default: false

pub fn with_underlines(self, enabled: bool) -> Self

Enable or disable underlines for highlighted spans.

When enabled, spans are underlined with characters like ^^^. When disabled, only label arrows are shown.

Works with both compact and non-compact modes.

Default: true

pub fn with_column_order(self, enabled: bool) -> Self

Enable or disable natural label ordering.

When disabled (default), labels are sorted to minimize line crossings:

• Inline labels appear first, ordered by reverse column position
• Multi-line labels follow, with tails before heads

When enabled, labels are simply sorted by column position.

Default: false (natural ordering enabled)

Example

let config = Config::new().with_column_order(true);  // Simple column order

pub fn with_align_messages(self, enabled: bool) -> Self

Enable or disable aligned label messages.

When enabled (default), label messages are aligned to the same column, producing a more structured appearance with longer arrows.

When disabled, messages are placed immediately after their arrows, creating more compact output.

Default: true (aligned)

Example

let config = Config::new().with_align_messages(false);  // Compact arrows

pub fn with_multiline_arrows(self, enabled: bool) -> Self

Enable or disable multiline arrows for labels.

When enabled, labels that span multiple lines will have arrows drawn across all covered lines.

Default: true

pub fn with_tab_width(self, width: i32) -> Self

Set the tab width for rendering.

Tab characters (\t) in source code are expanded to this many spaces.

Default: 4

Example

let config = Config::new().with_tab_width(8);  // 8-space tabs

pub fn with_limit_width(self, width: i32) -> Self

Set the width limit for line wrapping.

Lines longer than this width will be truncated with an ellipsis. Set to 0 for no limit (lines can be arbitrarily long).

Default: 0 (no limit)

Example

let config = Config::new().with_limit_width(80);  // Wrap at 80 columns

pub fn with_ambi_width(self, width: i32) -> Self

Set the ambiguous character width.

Some Unicode characters have ambiguous width (e.g., East Asian characters). This setting determines their display width:

• 1 - Treat as narrow (1 column)
• 2 - Treat as wide (2 columns)

Default: 1

Example

let config = Config::new().with_ambi_width(2);  // East Asian width

pub fn with_label_attach(self, attach: LabelAttach) -> Self

Set where labels attach to spans.

Controls the default attachment point for all labels. Individual labels can override this with Report::with_order.

Default: LabelAttach::Middle

pub fn with_index_type(self, index_type: IndexType) -> Self

Set the index type (character or byte).

Determines how span ranges are interpreted. See IndexType for details.

Default: IndexType::Char

pub fn with_char_set_ascii(self) -> Self

Set ASCII character set for rendering.

Uses ASCII characters (-, |, +, etc.) for box drawing. This is compatible with all terminals and file formats.

Example

Error: message
   ,-[ file.rs:1:1 ]
   |
 1 | code here
   | ^^|^
   |   `--- label
---'

pub fn with_char_set_unicode(self) -> Self

Set Unicode character set for rendering.

Uses Unicode box-drawing characters (─, │, ┬, etc.) for prettier output. Requires a terminal that supports Unicode.

Example

Error: message
   ╭─[ file.rs:1:1 ]
   │
 1 │ code here
   │ ──┬─
   │   ╰─── label
───╯

pub fn with_char_set(self, char_set: &'a CharSet) -> Self

Set a custom character set for rendering.

Allows fine-grained control over all box-drawing characters. The character set must outlive the config.

Example

let custom = CharSet {
    hbar: '=',
    vbar: '!',
    ..CharSet::ascii()
};
let config = Config::new().with_char_set(&custom);

pub fn with_color_default(self) -> Self

Enable default ANSI colors.

Uses the built-in color scheme with standard ANSI escape codes:

• Errors in red
• Warnings in yellow
• Margins in blue
• etc.

This is appropriate for terminal output.

pub fn with_color_disabled(self) -> Self

Disable color output.

All output will be plain text without ANSI escape codes. This is appropriate for file output or non-color terminals.

Default: colors are disabled

pub fn with_color<C>(self, color: &'a C) -> Self

where C: Color,

Set a custom color provider.

Trait Implementations

impl Clone for Config<'_>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Config<'_>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Config<'_>

fn default() -> Self

Returns the “default value” for a type.