feat(vectors): add formatter support

- add ToStringOpts, defFormat(), FORMATTER
- update AVec and GVec impls

packages/vectors/src/api.ts

@@ -306,3 +306,29 @@ export const Z4: ReadonlyVec = Object.freeze([0, 0, 1, 0]);
 export const W4: ReadonlyVec = Object.freeze([0, 0, 0, 1]);
 
 export type Template = (syms: string[], i?: number) => string;
+
+export interface ToStringOpts {
+    /**
+     * Number of fractional digits
+     *
+     * @defaultValue 3
+     */
+    prec: number;
+    /**
+     * If given, each formatted vector component will be padded to given number
+     * of characters.
+     */
+    width: number;
+    /**
+     * Inter-component delimiter.
+     *
+     * @defaultValue ", "
+     */
+    delim: string;
+    /**
+     * Prefix/suffix wrapper strings.
+     *
+     * @defaultValue "[" and "]"
+     */
+    wrap: ArrayLike<string>;
+}

packages/vectors/src/gvec.ts

@@ -7,6 +7,7 @@ import { eqDeltaS } from "./eqdelta";
 import { stridedValues } from "./internal/vec-utils";
 import { zeroes } from "./setn";
 import { setS } from "./sets";
+import { FORMATTER } from "./string";
 
 const SYM_B = "buf";
 const SYM_L = "length";
@@ -131,9 +132,7 @@ export const gvec = (
                         eqDeltaS(buf, o, size, eps, offset, 0, stride, 1);
                 case SYM_STR:
                     return () =>
-                        JSON.stringify([
-                            ...stridedValues(obj, size, offset, stride),
-                        ]);
+                        FORMATTER(stridedValues(obj, size, offset, stride));
                 default:
                     const j = parseInt(<string>id);
                     return !isNaN(j) && j >= 0 && j < size

packages/vectors/src/internal/avec.ts

@@ -1,5 +1,6 @@
 import type { NumericArray } from "@thi.ng/api";
 import type { StridedVec } from "../api";
+import { FORMATTER } from "../string";
 
 export abstract class AVec implements StridedVec {
     buf: NumericArray;
@@ -15,4 +16,8 @@ export abstract class AVec implements StridedVec {
     abstract get length(): number;
 
     abstract [Symbol.iterator](): IterableIterator<number>;
+
+    toString() {
+        return FORMATTER(this);
+    }
 }

packages/vectors/src/string.ts

@@ -0,0 +1,63 @@
+import { isFunction } from "@thi.ng/checks";
+import { float, floatFixedWidth, Stringer } from "@thi.ng/strings";
+import type { ToStringOpts } from "./api";
+
+/**
+ * Returns a new generic vector formatter for given options (all optional). The
+ * returned function accepts a single vector(like) value and returns its
+ * formatted string representation.
+ *
+ * @remarks
+ * See {@link ToStringOpts} for further details. Also see {@link setFormat} to
+ * set default formatter.
+ *
+ * @example
+ * ```ts
+ * defFormat()([1, -2, 3])
+ * // [1.000, -2.000, 3.000]
+ *
+ * defFormat({ width: 10, wrap: "||", delim: "|\n|" })([1, -2, 3])
+ * // |     1.000|
+ * // |    -2.000|
+ * // |     3.000|
+ *
+ * defFormat({ prec: 5, delim: " " })([1, -2, 3])
+ * // [1.00000 -2.00000 3.00000]
+ * ```
+ *
+ * @param prec
+ * @param width
+ */
+export const defFormat = (
+    opts?: Partial<ToStringOpts>
+): Stringer<Iterable<number>> => {
+    const { prec, width, delim, wrap } = {
+        prec: 3,
+        delim: ", ",
+        wrap: "[]",
+        ...opts,
+    };
+    const fmt = width ? floatFixedWidth(width, prec) : float(prec);
+    return (src) => {
+        let res: string[] = [];
+        for (let x of src) res.push(fmt(x));
+        return `${wrap[0]}${res.join(delim)}${wrap[1]}`;
+    };
+};
+
+/**
+ * Sets package-wide default vector formatter. See {@link defFormat},
+ * {@link FORMATTER}.
+ *
+ * @param fmt
+ */
+export const setFormat = (
+    fmt: Stringer<Iterable<number>> | Partial<ToStringOpts>
+) => {
+    FORMATTER = isFunction(fmt) ? fmt : defFormat(fmt);
+};
+
+/**
+ * Package-wide default vector formatter.
+ */
+export let FORMATTER: Stringer<Iterable<number>> = defFormat();

packages/vectors/src/vec2.ts

@@ -124,10 +124,6 @@ export class Vec2 extends AVec implements IHash<number>, IVector<Vec2> {
     toJSON() {
         return [this.x, this.y];
     }
-
-    toString() {
-        return `[${this.x}, ${this.y}]`;
-    }
 }
 
 declareIndices(Vec2.prototype, ["x", "y"]);

packages/vectors/src/vec3.ts

@@ -127,10 +127,6 @@ export class Vec3 extends AVec implements IHash<number>, IVector<Vec3> {
     toJSON() {
         return [this.x, this.y, this.z];
     }
-
-    toString() {
-        return `[${this.x}, ${this.y}, ${this.z}]`;
-    }
 }
 
 declareIndices(Vec3.prototype, ["x", "y", "z"]);

packages/vectors/src/vec4.ts

@@ -128,10 +128,6 @@ export class Vec4 extends AVec implements IHash<number>, IVector<Vec4> {
     toJSON() {
         return [this.x, this.y, this.z, this.w];
     }
-
-    toString() {
-        return `[${this.x}, ${this.y}, ${this.z}, ${this.w}]`;
-    }
 }
 
 declareIndices(Vec4.prototype, ["x", "y", "z", "w"]);