#50 - regexp and by-name matching support for target-folder

- complete implementation
- full unit tests coverage
- NO update to documentation (yet to be done)

src/custom-sort/custom-sort-types.ts

@@ -64,6 +64,7 @@ export interface CustomSortGroup {
 }
 
 export interface CustomSortSpec {
+		// plays only informative role about the original parsed 'target-folder:' values
 	targetFoldersPaths: Array<string>   // For root use '/'
 	defaultOrder?: CustomSortOrder
 	byMetadataField?: string            // for 'by-metadata:' if the defaultOrder is by metadata alphabetical or reverse

src/custom-sort/folder-matching-rules.spec.ts

@@ -14,6 +14,43 @@ const createMockMatcherRichVersion = (): FolderWildcardMatching<SortingSpec> =>
 	return matcher
 }
 
+const PRIO1 = 1
+const PRIO2 = 2
+const PRIO3 = 3
+
+const createMockMatcherRichWithRegexpVersion = (usePriorities?: boolean): FolderWildcardMatching<SortingSpec> => {
+	const matcher: FolderWildcardMatching<SortingSpec> = createMockMatcherRichVersion()
+	let p: RegExp
+	const {row3, row4, row5, row6} = usePriorities ?
+		{row3: PRIO1, row4: PRIO1, row5: PRIO2, row6: PRIO3}
+		:
+		{row3:undefined, row4:undefined, row5:undefined, row6:undefined}
+	p = /.../; matcher.addRegexpDefinition(p, true, undefined, false, `r1`)
+	p = /^\/$/; matcher.addRegexpDefinition(p, false, undefined, false, `r2`)
+	p = /^Arc..ve$/; matcher.addRegexpDefinition(p, true, row3, false, `r3`)
+	p = /^Arc..ve$/; matcher.addRegexpDefinition(p, false, row4, false, `r4`)
+	p = /Reviews\/daily\/a\/.../; matcher.addRegexpDefinition(p, true, row5, false, `r5`)
+	p = /Reviews\/daily\/a\/*/; matcher.addRegexpDefinition(p, true, row6, false, `r6`)
+	return matcher
+}
+
+/*
+tests needed:
+√ regexp-match by name works (ensure regexp input is the name)
+√ regexp-match by path works (ensure regexp input is the path)
+√ regexp-match by name works and has priority over wildcard
+√ regexp-match by path works and has priority over wildcard
+√ regexp-match by name vs by path is equal, order of definition matters (test two variants)
+- priority /!!!: is higher over /!!:
+- priority /!!: is higher over /!:
+- priority /!: is higher over no-priority
+  - test adding priorities in all possible orders
+  - within the same priority the order of definition matters
+
+- edge case -> root folder, has no name, has specific path '/', matching by name should not work, only by path
+  - what is the root folder name ???
+ */
+
 const createMockMatcherSimplestVersion = (): FolderWildcardMatching<SortingSpec> => {
 	const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
 	matcher.addWildcardDefinition('/Reviews/daily/*', '/Reviews/daily/*')
@@ -117,4 +154,137 @@ describe('folderMatch', () => {
 
 		expect(result).toEqual({errorMsg: "Duplicate wildcard '*' specification for Archive/2019/*"})
 	})
+	it('regexp-match by name works (order of regexp doesn\'t matter) case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^daily$/, false, undefined, false, `r1`)
+		matcher.addRegexpDefinition(/^daily$/, true, undefined, false, `r2`)
+		matcher.addWildcardDefinition('/Reviews/*', `w1`)
+		  // Path with leading /
+		const match1: SortingSpec | null = matcher.folderMatch('/Reviews/daily', 'daily')
+		  // Path w/o leading / - this is how Obsidian supplies the path
+		const match2: SortingSpec | null = matcher.folderMatch('Reviews/daily', 'daily')
+		expect(match1).toBe('r2')
+		expect(match2).toBe('r2')
+	})
+	it('regexp-match by name works (order of regexp doesn\'t matter) reversed case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^daily$/, true, undefined, false, `r2`)
+		matcher.addRegexpDefinition(/^daily$/, false, undefined, false, `r1`)
+		matcher.addWildcardDefinition('/Reviews/*', `w1`)
+		  // Path with leading /
+		const match1: SortingSpec | null = matcher.folderMatch('/Reviews/daily', 'daily')
+		  // Path w/o leading / - this is how Obsidian supplies the path
+		const match2: SortingSpec | null = matcher.folderMatch('Reviews/daily', 'daily')
+		expect(match1).toBe('r2')
+		expect(match2).toBe('r2')
+	})
+	it('regexp-match by path works (order of regexp doesn\'t matter) case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^Reviews\/daily$/, false, undefined, false, `r1`)
+		matcher.addRegexpDefinition(/^Reviews\/daily$/, true, undefined, false, `r2`)
+		matcher.addWildcardDefinition('/Reviews/*', `w1`)
+		  // Path with leading /
+		const match1: SortingSpec | null = matcher.folderMatch('/Reviews/daily', 'daily')
+		  // Path w/o leading / - this is how Obsidian supplies the path
+		const match2: SortingSpec | null = matcher.folderMatch('Reviews/daily', 'daily')
+		expect(match1).toBe('w1')  // The path-based regexp doesn't match the leading /
+		expect(match2).toBe('r1')
+	})
+	it('regexp-match by path works (order of regexp doesn\'t matter) reversed case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^Reviews\/daily$/, true, undefined, false, `r2`)
+		matcher.addRegexpDefinition(/^Reviews\/daily$/, false, undefined, false, `r1`)
+		matcher.addWildcardDefinition('/Reviews/*', `w1`)
+		// Path with leading /
+		const match1: SortingSpec | null = matcher.folderMatch('/Reviews/daily', 'daily')
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match2: SortingSpec | null = matcher.folderMatch('Reviews/daily', 'daily')
+		expect(match1).toBe('w1')  // The path-based regexp doesn't match the leading /
+		expect(match2).toBe('r1')
+	})
+	it('regexp-match by path and name for root level - order of regexp decides - case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^daily$/, false, undefined, false, `r1`)
+		matcher.addRegexpDefinition(/^daily$/, true, undefined, false, `r2`)
+		matcher.addWildcardDefinition('/Reviews/*', `w1`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('daily', 'daily')
+		expect(match).toBe('r2')
+	})
+	it('regexp-match by path and name for root level - order of regexp decides - reversed case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^daily$/, true, undefined, false, `r2`)
+		matcher.addRegexpDefinition(/^daily$/, false, undefined, false, `r1`)
+		matcher.addWildcardDefinition('/Reviews/*', `w1`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('daily', 'daily')
+		expect(match).toBe('r1')
+	})
+	it('regexp-match priorities - order of definitions irrelevant - unique priorities - case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 3, false, `r1p3`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 2, false, `r2p2`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 1, false, `r3p1`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, undefined, false, `r4pNone`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('freq/daily', 'daily')
+		expect(match).toBe('r1p3')
+	})
+	it('regexp-match priorities - order of definitions irrelevant - unique priorities - reversed case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, undefined, false, `r4pNone`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 1, false, `r3p1`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 2, false, `r2p2`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 3, false, `r1p3`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('freq/daily', 'daily')
+		expect(match).toBe('r1p3')
+	})
+	it('regexp-match priorities - order of definitions irrelevant - duplicate priorities - case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^daily$/, true, 3, false, `r1p3a`)
+		matcher.addRegexpDefinition(/^daily$/, true, 3, false, `r1p3b`)
+		matcher.addRegexpDefinition(/^daily$/, true, 2, false, `r2p2a`)
+		matcher.addRegexpDefinition(/^daily$/, true, 2, false, `r2p2b`)
+		matcher.addRegexpDefinition(/^daily$/, true, 1, false, `r3p1a`)
+		matcher.addRegexpDefinition(/^daily$/, true, 1, false, `r3p1b`)
+		matcher.addRegexpDefinition(/^daily$/, true, undefined, false, `r4pNone`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('daily', 'daily')
+		expect(match).toBe('r1p3b')
+	})
+	it('regexp-match priorities - order of definitions irrelevant - unique priorities - reversed case A', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, undefined, false, `r4pNone`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 1, false, `r3p1`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 2, false, `r2p2`)
+		matcher.addRegexpDefinition(/^freq\/daily$/, false, 3, false, `r1p3`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('freq/daily', 'daily')
+		expect(match).toBe('r1p3')
+	})
+	it('regexp-match - edge case of matching the root folder - match by path', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		matcher.addRegexpDefinition(/^\/$/, false, undefined, false, `r1`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('/', '')
+		expect(match).toBe('r1')
+	})
+	it('regexp-match - edge case of matching the root folder - match by name not possible', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		  // Tricky regexp which can return zero length matches
+		matcher.addRegexpDefinition(/.*/, true, undefined, false, `r1`)
+		matcher.addWildcardDefinition('/*', `w1`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('/', '')
+		expect(match).toBe('w1')
+	})
+	it('regexp-match - edge case of no match when only regexp rules present', () => {
+		const matcher: FolderWildcardMatching<SortingSpec> = new FolderWildcardMatching()
+		// Tricky regexp which can return zero length matches
+		matcher.addRegexpDefinition(/abc/, true, undefined, false, `r1`)
+		// Path w/o leading / - this is how Obsidian supplies the path
+		const match: SortingSpec | null = matcher.folderMatch('/', '')
+		expect(match).toBeNull()
+	})
 })

src/custom-sort/folder-matching-rules.ts

@@ -1,8 +1,4 @@
-export interface FolderPattern {
+import * as regexpp from "regexpp";
-	path: string
-	deep: boolean
-	nestingLevel: number
-}
 
 export type DeterminedSortingSpec<SortingSpec> = {
 	spec?: SortingSpec
@@ -16,6 +12,14 @@ export interface FolderMatchingTreeNode<SortingSpec> {
 	subtree: { [key: string]: FolderMatchingTreeNode<SortingSpec> }
 }
 
+export interface FolderMatchingRegexp<SortingSpec> {
+	regexp: RegExp
+	againstName: boolean
+	priority: number
+	logMatches: boolean
+	sortingSpec: SortingSpec
+}
+
 const SLASH: string = '/'
 export const MATCH_CHILDREN_PATH_TOKEN: string = '...'
 export const MATCH_ALL_PATH_TOKEN: string = '*'
@@ -23,6 +27,7 @@ export const MATCH_CHILDREN_1_SUFFIX: string = `/${MATCH_CHILDREN_PATH_TOKEN}`
 export const MATCH_CHILDREN_2_SUFFIX: string = `/${MATCH_CHILDREN_PATH_TOKEN}/`
 export const MATCH_ALL_SUFFIX: string = `/${MATCH_ALL_PATH_TOKEN}`
 
+export const NO_PRIORITY = 0
 
 export const splitPath = (path: string): Array<string> => {
 	return path.split(SLASH).filter((name) => !!name)
@@ -34,10 +39,13 @@ export interface AddingWildcardFailure {
 
 export class FolderWildcardMatching<SortingSpec> {
 
+	// mimics the structure of folders, so for example tree.matchAll contains the matchAll flag for the root '/'
 	tree: FolderMatchingTreeNode<SortingSpec> = {
 		subtree: {}
 	}
 
+	regexps: Array<FolderMatchingRegexp<SortingSpec>>
+
 	// cache
 	determinedWildcardRules: { [key: string]: DeterminedSortingSpec<SortingSpec> } = {}
 
@@ -76,13 +84,61 @@ export class FolderWildcardMatching<SortingSpec> {
 		}
 	}
 
-	folderMatch = (folderPath: string): SortingSpec | null => {
+	addRegexpDefinition = (regexp: RegExp,
+						   againstName: boolean,
+						   priority: number | undefined,
+						   log: boolean | undefined,
+						   rule: SortingSpec
+	) => {
+		const newItem: FolderMatchingRegexp<SortingSpec> = {
+			regexp: regexp,
+			againstName: againstName,
+			priority: priority || NO_PRIORITY,
+			sortingSpec: rule,
+			logMatches: !!log
+		}
+		if (this.regexps === undefined || this.regexps.length === 0) {
+			this.regexps = [newItem]
+		} else {
+			// priority is present ==> consciously determine where to insert the regexp
+			let idx = 0
+			while (idx < this.regexps.length && this.regexps[idx].priority > newItem.priority) {
+				idx++
+			}
+			this.regexps.splice(idx, 0, newItem)
+		}
+	}
+
+	folderMatch = (folderPath: string, folderName?: string): SortingSpec | null => {
 		const spec: DeterminedSortingSpec<SortingSpec> = this.determinedWildcardRules[folderPath]
 
 		if (spec) {
 			return spec.spec ?? null
 		} else {
-			let rule: SortingSpec | null | undefined = this.tree.matchChildren
+			let rule: SortingSpec | null | undefined
+			// regexp matching
+			if (this.regexps) {
+				for (let r of this.regexps) {
+					if (r.againstName && !folderName) {
+						// exclude the edge case:
+						// - root folder which has empty name (and path /)
+						// AND name-matching regexp allows zero-length matches
+						continue
+					}
+					if (r.regexp.test(r.againstName ? (folderName || '') : folderPath)) {
+						rule = r.sortingSpec
+						if (r.logMatches) {
+							const msgDetails: string = (r.againstName) ? `name: ${folderName}` : `path: ${folderPath}`
+							console.log(`custom-sort plugin - regexp <${r.regexp.source}> matched folder ${msgDetails}`)
+						}
+						break
+					}
+				}
+			}
+
+			// simple wildards matching
+			if (!rule) {
+				rule = this.tree.matchChildren
 				let inheritedRule: SortingSpec | undefined = this.tree.matchAll
 				const pathComponents: Array<string> = splitPath(folderPath)
 				let parentNode: FolderMatchingTreeNode<SortingSpec> = this.tree
@@ -103,6 +159,7 @@ export class FolderWildcardMatching<SortingSpec> {
 				}
 
 				rule = rule ?? inheritedRule
+			}
 
 			if (rule) {
 				this.determinedWildcardRules[folderPath] = {spec: rule}

src/custom-sort/sorting-spec-processor.spec.ts

@@ -780,6 +780,170 @@ describe('SortingSpecProcessor edge case', () => {
 	})
 })
 
+const txtInputTargetFolderByName: string = `
+target-folder: name: TheName
+< a-z
+`
+
+const txtInputTargetFolderWithRegex: string = `
+> advanced modified
+target-folder: name: TheName
+< a-z
+target-folder: regexp: r1
+target-folder: regexp: /!!: r2*
+target-folder: regexp: for-name: r3.{2-3}$
+target-folder: regexp: for-name: /!: r4\\d
+target-folder: regexp: for-name: /!!: ^r5[^[]+
+target-folder: regexp: for-name: /!!!: ^r6/+$
+target-folder: regexp: debug: r7 +
+target-folder: regexp: for-name: debug: r8 (aa|bb|cc)
+target-folder: regexp: for-name: /!!!: debug: r9 [abc]+
+target-folder: regexp: /!: debug: ^r10 /[^/]/.+$
+`
+
+const expectedSortSpecTargetFolderRegexAndName1 = {
+	defaultOrder: CustomSortOrder.byModifiedTimeReverseAdvanced,
+	groups: [{
+		order: CustomSortOrder.byModifiedTimeReverseAdvanced,
+		type: CustomSortGroupType.Outsiders
+	}],
+	outsidersGroupIdx: 0,
+	targetFoldersPaths: ['mock-folder']
+}
+
+const expectedSortSpecTargetFolderByName = {
+	defaultOrder: CustomSortOrder.alphabetical,
+	groups: [{
+		order: CustomSortOrder.alphabetical,
+		type: CustomSortGroupType.Outsiders
+	}],
+	outsidersGroupIdx: 0,
+	targetFoldersPaths: ['name: TheName']
+}
+
+const expectedSortSpecsTargetFolderByPathInRegexTestCase: { [key: string]: CustomSortSpec } = {
+	'mock-folder': expectedSortSpecTargetFolderRegexAndName1
+}
+
+const expectedSortSpecsTargetFolderByName: { [key: string]: CustomSortSpec } = {
+	'TheName': expectedSortSpecTargetFolderByName
+}
+
+const expectedSortSpecForRegexpTextCase = {
+	groups: [{
+		order: CustomSortOrder.alphabetical,
+		type: CustomSortGroupType.Outsiders
+	}],
+	outsidersGroupIdx: 0,
+	targetFoldersPaths: [
+		"regexp: r1",
+		"regexp: /!!: r2*",
+		"regexp: for-name: r3.{2-3}$",
+		"regexp: for-name: /!: r4\\d",
+		"regexp: for-name: /!!: ^r5[^[]+",
+		"regexp: for-name: /!!!: ^r6/+$",
+		"regexp: debug: r7 +",
+		"regexp: for-name: debug: r8 (aa|bb|cc)",
+		"regexp: for-name: /!!!: debug: r9 [abc]+",
+		"regexp: /!: debug: ^r10 /[^/]/.+$"
+	]
+}
+
+const expectedTargetFolderRegexpArr = [
+	{
+		regexp: /r9 [abc]+/,
+		againstName: true,
+		priority: 3,
+		logMatches: true,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /^r6\/+$/,
+		againstName: true,
+		priority: 3,
+		logMatches: false,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /^r5[^[]+/,
+		againstName: true,
+		priority: 2,
+		logMatches: false,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /r2*/,
+		againstName: false,
+		priority: 2,
+		logMatches: false,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /^r10 \/[^/]\/.+$/,
+		againstName: false,
+		priority: 1,
+		logMatches: true,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /r4\d/,
+		againstName: true,
+		priority: 1,
+		logMatches: false,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /r8 (aa|bb|cc)/,
+		againstName: true,
+		priority: 0,
+		logMatches: true,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /r7 +/,
+		againstName: false,
+		priority: 0,
+		logMatches: true,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /r3.{2-3}$/,
+		againstName: true,
+		priority: 0,
+		logMatches: false,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	},
+	{
+		regexp: /r1/,
+		againstName: false,
+		priority: 0,
+		logMatches: false,
+		sortingSpec: expectedSortSpecForRegexpTextCase
+	}
+]
+
+describe('SortingSpecProcessor target-folder by name and regex', () => {
+	let processor: SortingSpecProcessor;
+	beforeEach(() => {
+		processor = new SortingSpecProcessor();
+	});
+	it('should correctly handle the by-name only target-folder', () => {
+		const inputTxtArr: Array<string> = txtInputTargetFolderByName.split('\n')
+		const result = processor.parseSortSpecFromText(inputTxtArr, 'mock-folder', 'custom-name-note.md')
+		expect(result?.sortSpecByPath).toEqual({})
+		expect(result?.sortSpecByName).toEqual(expectedSortSpecsTargetFolderByName)
+		expect(result?.sortSpecByWildcard).not.toBeNull()
+	})
+	it('should recognize and correctly parse target folder by name with and w/o regexp variants', () => {
+		const inputTxtArr: Array<string> = txtInputTargetFolderWithRegex.split('\n')
+		const result = processor.parseSortSpecFromText(inputTxtArr, 'mock-folder', 'custom-name-note.md')
+		expect(result?.sortSpecByPath).toEqual(expectedSortSpecsTargetFolderByPathInRegexTestCase)
+		expect(result?.sortSpecByName).toEqual(expectedSortSpecsTargetFolderByName)
+		expect(result?.sortSpecByWildcard?.tree).toEqual({subtree: {}})
+		expect(result?.sortSpecByWildcard?.regexps).toEqual(expectedTargetFolderRegexpArr)
+	})
+})
+
 const txtInputPriorityGroups1: string = `
 target-folder: /
 /:files
@@ -1694,6 +1858,48 @@ describe('SortingSpecProcessor error detection and reporting', () => {
 		expect(result).not.toBeNull()
 		expect(errorsLogger).not.toHaveBeenCalled()
 	})
+	it('should recognize empty regexp of target-folder:', () => {
+		const inputTxtArr: Array<string> = `
+		target-folder: regexp:  
+		`.replace(/\t/gi, '').split('\n')
+		const result = processor.parseSortSpecFromText(inputTxtArr, 'mock-folder', 'custom-name-note.md')
+		expect(result).toBeNull()
+		expect(errorsLogger).toHaveBeenCalledTimes(1)
+		expect(errorsLogger).toHaveBeenNthCalledWith(1,
+			`${ERR_PREFIX} 27:InvalidOrEmptyFolderMatchingRegexp Invalid or empty folder regexp expression <> ${ERR_SUFFIX}`)
+	})
+	it('should recognize error in regexp of target-folder:', () => {
+		const inputTxtArr: Array<string> = `
+		target-folder: regexp: bla (
+		`.replace(/\t/gi, '').split('\n')
+		const result = processor.parseSortSpecFromText(inputTxtArr, 'mock-folder', 'custom-name-note.md')
+		expect(result).toBeNull()
+		expect(errorsLogger).toHaveBeenCalledTimes(1)
+		expect(errorsLogger).toHaveBeenNthCalledWith(1,
+			`${ERR_PREFIX} 27:InvalidOrEmptyFolderMatchingRegexp Invalid or empty folder regexp expression <bla (> ${ERR_SUFFIX}`)
+	})
+	it('should recognize empty name in target-folder: name:', () => {
+		const inputTxtArr: Array<string> = `
+		target-folder: name:      
+		`.replace(/\t/gi, '').split('\n')
+		const result = processor.parseSortSpecFromText(inputTxtArr, 'mock-folder', 'custom-name-note.md')
+		expect(result).toBeNull()
+		expect(errorsLogger).toHaveBeenCalledTimes(1)
+		expect(errorsLogger).toHaveBeenNthCalledWith(1,
+			`${ERR_PREFIX} 26:EmptyFolderNameToMatch Empty 'target-folder: name:' value ${ERR_SUFFIX}`)
+	})
+	it('should recognize duplicate name in target-folder: name:', () => {
+		const inputTxtArr: Array<string> = `
+		target-folder: name: 123
+		target-folder: name: xyz
+		target-folder: name: 123
+		`.replace(/\t/gi, '').split('\n')
+		const result = processor.parseSortSpecFromText(inputTxtArr, 'mock-folder', 'custom-name-note.md')
+		expect(result).toBeNull()
+		expect(errorsLogger).toHaveBeenCalledTimes(1)
+		expect(errorsLogger).toHaveBeenNthCalledWith(1,
+			`${ERR_PREFIX} 25:DuplicateByNameSortSpecForFolder Duplicate 'target-folder: name:' definition for the same name <123> ${ERR_SUFFIX}`)
+	})
 })
 
 const txtInputTargetFolderCCC: string = `

src/custom-sort/sorting-spec-processor.ts

@@ -25,7 +25,8 @@ import {
 	FolderWildcardMatching,
 	MATCH_ALL_SUFFIX,
 	MATCH_CHILDREN_1_SUFFIX,
-	MATCH_CHILDREN_2_SUFFIX
+	MATCH_CHILDREN_2_SUFFIX,
+	NO_PRIORITY
 } from "./folder-matching-rules"
 
 interface ProcessingContext {
@@ -75,13 +76,19 @@ export enum ProblemCode {
 	TooManyGroupTypePrefixes,
 	PriorityPrefixAfterGroupTypePrefix,
 	CombinePrefixAfterGroupTypePrefix,
-	InlineRegexInPrefixAndSuffix
+	InlineRegexInPrefixAndSuffix,
+	DuplicateByNameSortSpecForFolder,
+	EmptyFolderNameToMatch,
+	InvalidOrEmptyFolderMatchingRegexp
 }
 
 const ContextFreeProblems = new Set<ProblemCode>([
 	ProblemCode.DuplicateSortSpecForSameFolder,
 	ProblemCode.DuplicateWildcardSortSpecForSameFolder,
-	ProblemCode.OnlyLastCombinedGroupCanSpecifyOrder
+	ProblemCode.OnlyLastCombinedGroupCanSpecifyOrder,
+	ProblemCode.DuplicateByNameSortSpecForFolder,
+	ProblemCode.EmptyFolderNameToMatch,
+	ProblemCode.InvalidOrEmptyFolderMatchingRegexp
 ])
 
 const ThreeDots = '...';
@@ -157,9 +164,11 @@ enum Attribute {
 	OrderStandardObsidian
 }
 
+const TargetFolderLexeme: string = 'target-folder:'
+
 const AttrLexems: { [key: string]: Attribute } = {
 	// Verbose attr names
-	'target-folder:': Attribute.TargetFolder,
+	[TargetFolderLexeme]: Attribute.TargetFolder,
 	'order-asc:': Attribute.OrderAsc,
 	'order-desc:': Attribute.OrderDesc,
 	'sorting:': Attribute.OrderStandardObsidian,
@@ -203,6 +212,10 @@ const PriorityModifierPrio1Lexeme: string = '/!'
 const PriorityModifierPrio2Lexeme: string = '/!!'
 const PriorityModifierPrio3Lexeme: string = '/!!!'
 
+const PriorityModifierPrio1TargetFolderLexeme: string = '/!:'
+const PriorityModifierPrio2TargetFolderLexeme: string = '/!!:'
+const PriorityModifierPrio3TargetFolderLexeme: string = '/!!!:'
+
 const PRIO_1: number = 1
 const PRIO_2: number = 2
 const PRIO_3: number = 3
@@ -213,6 +226,12 @@ const SortingGroupPriorityPrefixes: { [key: string]: number } = {
 	[PriorityModifierPrio3Lexeme]: PRIO_3
 }
 
+const TargetFolderRegexpPriorityPrefixes: { [key: string]: number } = {
+	[PriorityModifierPrio1TargetFolderLexeme]: PRIO_1,
+	[PriorityModifierPrio2TargetFolderLexeme]: PRIO_2,
+	[PriorityModifierPrio3TargetFolderLexeme]: PRIO_3
+}
+
 const CombineGroupLexeme: string = '/+'
 
 const CombiningGroupPrefixes: Array<string> = [
@@ -491,15 +510,35 @@ export const convertInlineRegexSymbolsAndEscapeTheRest = (s: string): RegexAsStr
 	return regexAsString.join('')
 }
 
+export const MatchFolderNameLexeme: string = 'name:'
+export const MatchFolderByRegexpLexeme: string = 'regexp:'
+export const RegexpAgainstFolderName: string = 'for-name:'
+export const DebugFolderRegexMatchesLexeme: string = 'debug:'
+
+type FolderPath = string
+type FolderName = string
+
 export interface FolderPathToSortSpecMap {
-	[key: string]: CustomSortSpec
+	[key: FolderPath]: CustomSortSpec
+}
+
+export interface FolderNameToSortSpecMap {
+	[key: FolderName]: CustomSortSpec
 }
 
 export interface SortSpecsCollection {
 	sortSpecByPath: FolderPathToSortSpecMap
+	sortSpecByName: FolderNameToSortSpecMap
 	sortSpecByWildcard?: FolderWildcardMatching<CustomSortSpec>
 }
 
+export const newSortSpecsCollection = (): SortSpecsCollection => {
+	return {
+		sortSpecByPath: {},
+		sortSpecByName: {}
+	}
+}
+
 interface AdjacencyInfo {
 	noPrefix: boolean,
 	noSuffix: boolean
@@ -524,32 +563,78 @@ enum WildcardPriority {
 	MATCH_ALL
 }
 
-const stripWildcardPatternSuffix = (path: string): [path: string, priority: number] => {
+const stripWildcardPatternSuffix = (path: string): {path: string, detectedWildcardPriority: number} => {
 	if (path.endsWith(MATCH_ALL_SUFFIX)) {
 		path = path.slice(0, -MATCH_ALL_SUFFIX.length)
-		return [
+		return {
-			path.length > 0 ? path : '/',
+			path: path.length > 0 ? path : '/',
-			WildcardPriority.MATCH_ALL
+			detectedWildcardPriority: WildcardPriority.MATCH_ALL
-		]
+		}
 	}
 	if (path.endsWith(MATCH_CHILDREN_1_SUFFIX)) {
 		path = path.slice(0, -MATCH_CHILDREN_1_SUFFIX.length)
-		return [
+		return {
-			path.length > 0 ? path : '/',
+			path: path.length > 0 ? path : '/',
-			WildcardPriority.MATCH_CHILDREN,
+			detectedWildcardPriority: WildcardPriority.MATCH_CHILDREN,
-		]
+		}
 	}
 	if (path.endsWith(MATCH_CHILDREN_2_SUFFIX)) {
 		path = path.slice(0, -MATCH_CHILDREN_2_SUFFIX.length)
-		return [
+		return {
-			path.length > 0 ? path : '/',
+			path: path.length > 0 ? path : '/',
-			WildcardPriority.MATCH_CHILDREN
+			detectedWildcardPriority: WildcardPriority.MATCH_CHILDREN
-		]
+		}
+	}
+	return {
+		path: path,
+		detectedWildcardPriority: WildcardPriority.NO_WILDCARD
+	}
+}
+
+const eatPrefixIfPresent = (expression: string, prefix: string, onDetected: () => void): string => {
+	const detected: boolean = expression.startsWith(prefix)
+	if (detected) {
+		onDetected()
+		return expression.substring(prefix.length).trim()
+	} else {
+		return expression
+	}
+}
+
+const consumeFolderByRegexpExpression = (expression: string): {regexp: RegExp, againstName: boolean, priority: number | undefined, log: boolean | undefined} => {
+	let againstName: boolean = false
+	let priority: number | undefined
+	let logMatches: boolean | undefined
+
+	// For simplicity, strict imposed order of regexp-specific attributes
+	expression = eatPrefixIfPresent(expression, RegexpAgainstFolderName, () => {
+		againstName = true
+	})
+
+	for (const priorityPrefix of Object.keys(TargetFolderRegexpPriorityPrefixes)) {
+		expression = eatPrefixIfPresent(expression, priorityPrefix, () => {
+			priority = TargetFolderRegexpPriorityPrefixes[priorityPrefix]
+		})
+		if (priority) {
+			break
+		}
+	}
+
+	expression = eatPrefixIfPresent(expression, DebugFolderRegexMatchesLexeme, () => {
+		logMatches = true
+	})
+
+	// do not allow empty regexp
+	if (!expression || expression.trim() === '') {
+		throw new Error('Empty regexp')
+	}
+
+	return {
+		regexp: new RegExp(expression),
+		againstName: againstName,
+		priority: priority === undefined ? NO_PRIORITY : priority,
+		log: !!logMatches
 	}
-	return [
-		path,
-		WildcardPriority.NO_WILDCARD
-	]
 }
 
 // Simplistic
@@ -641,12 +726,52 @@ export class SortingSpecProcessor {
 					}
 				}
 
-				let sortspecByWildcard: FolderWildcardMatching<CustomSortSpec> | undefined
+				let sortspecByName: FolderNameToSortSpecMap | undefined
 				for (let spec of this.ctx.specs) {
-					// Consume the folder paths ending with wildcard specs
+					// Consume the folder names prefixed by the designated lexeme
 					for (let idx = 0; idx<spec.targetFoldersPaths.length; idx++) {
 						const path = spec.targetFoldersPaths[idx]
-						if (endsWithWildcardPatternSuffix(path)) {
+						if (path.startsWith(MatchFolderNameLexeme)) {
+							const folderNameToMatch: string = path.substring(MatchFolderNameLexeme.length).trim()
+							if (folderNameToMatch === '') {
+								this.problem(ProblemCode.EmptyFolderNameToMatch,
+									`Empty '${TargetFolderLexeme} ${MatchFolderNameLexeme}' value` )
+								return null // Failure - not allow duplicate by folderNameToMatch specs for the same folder folderNameToMatch
+							}
+							sortspecByName = sortspecByName ?? {}
+							if (sortspecByName[folderNameToMatch]) {
+								this.problem(ProblemCode.DuplicateByNameSortSpecForFolder,
+									`Duplicate '${TargetFolderLexeme} ${MatchFolderNameLexeme}' definition for the same name <${folderNameToMatch}>` )
+								return null // Failure - not allow duplicate by folderNameToMatch specs for the same folder folderNameToMatch
+							} else {
+								sortspecByName[folderNameToMatch] = spec
+							}
+						}
+					}
+				}
+
+				if (sortspecByName) {
+					collection = collection ?? newSortSpecsCollection()
+					collection.sortSpecByName = sortspecByName
+				}
+
+				let sortspecByWildcard: FolderWildcardMatching<CustomSortSpec> | undefined
+				for (let spec of this.ctx.specs) {
+					// Consume the folder paths ending with wildcard specs or regexp-based
+					for (let idx = 0; idx<spec.targetFoldersPaths.length; idx++) {
+						const path = spec.targetFoldersPaths[idx]
+						if (path.startsWith(MatchFolderByRegexpLexeme)) {
+							sortspecByWildcard = sortspecByWildcard ?? new FolderWildcardMatching<CustomSortSpec>()
+							const folderByRegexpExpression: string = path.substring(MatchFolderByRegexpLexeme.length).trim()
+							try {
+								const {regexp, againstName, priority, log} = consumeFolderByRegexpExpression(folderByRegexpExpression)
+								sortspecByWildcard.addRegexpDefinition(regexp, againstName, priority, log, spec)
+							} catch (e) {
+								this.problem(ProblemCode.InvalidOrEmptyFolderMatchingRegexp,
+									`Invalid or empty folder regexp expression <${folderByRegexpExpression}>`)
+								return null
+							}
+						} else if (endsWithWildcardPatternSuffix(path)) {
 							sortspecByWildcard = sortspecByWildcard ?? new FolderWildcardMatching<CustomSortSpec>()
 							const ruleAdded = sortspecByWildcard.addWildcardDefinition(path, spec)
 							if (ruleAdded?.errorMsg) {
@@ -658,17 +783,16 @@ export class SortingSpecProcessor {
 				}
 
 				if (sortspecByWildcard) {
-					collection = collection ?? { sortSpecByPath:{} }
+					collection = collection ?? newSortSpecsCollection()
 					collection.sortSpecByWildcard = sortspecByWildcard
 				}
 
 				for (let spec of this.ctx.specs) {
 					for (let idx = 0; idx < spec.targetFoldersPaths.length; idx++) {
 						const originalPath = spec.targetFoldersPaths[idx]
-						collection = collection ?? { sortSpecByPath: {} }
+						if (!originalPath.startsWith(MatchFolderNameLexeme) && !originalPath.startsWith(MatchFolderByRegexpLexeme)) {
-						let detectedWildcardPriority: WildcardPriority
+							collection = collection ?? newSortSpecsCollection()
-						let path: string
+							const {path, detectedWildcardPriority} = stripWildcardPatternSuffix(originalPath)
-						[path, detectedWildcardPriority] = stripWildcardPatternSuffix(originalPath)
 							let storeTheSpec: boolean = true
 							const preexistingSortSpecPriority: WildcardPriority = this.pathMatchPriorityForPath[path]
 							if (preexistingSortSpecPriority) {
@@ -687,6 +811,7 @@ export class SortingSpecProcessor {
 						}
 					}
 				}
+			}
 			return collection
 		} else {
 			return null

src/main.ts

@@ -32,15 +32,13 @@ interface CustomSortPluginSettings {
 	suspended: boolean
 	statusBarEntryEnabled: boolean
 	notificationsEnabled: boolean
-	allowRegexpInTargetFolder: boolean
 }
 
 const DEFAULT_SETTINGS: CustomSortPluginSettings = {
 	additionalSortspecFile: '',
 	suspended: true,  // if false by default, it would be hard to handle the auto-parse after plugin install
 	statusBarEntryEnabled: true,
-	notificationsEnabled: true,
+	notificationsEnabled: true
-	allowRegexpInTargetFolder: false
 }
 
 const SORTSPEC_FILE_NAME: string = 'sortspec.md'
@@ -323,15 +321,16 @@ export default class CustomSortPlugin extends Plugin {
 						// if custom sort is not specified, use the UI-selected
 						const folder: TFolder = this.file
 						let sortSpec: CustomSortSpec | null | undefined = plugin.sortSpecCache?.sortSpecByPath[folder.path]
+						sortSpec = sortSpec ?? plugin.sortSpecCache?.sortSpecByName[folder.name]
 						if (sortSpec) {
 							if (sortSpec.defaultOrder === CustomSortOrder.standardObsidian) {
 								sortSpec = null // A folder is explicitly excluded from custom sorting plugin
 							}
 						} else if (plugin.sortSpecCache?.sortSpecByWildcard) {
 							// when no sorting spec found directly by folder path, check for wildcard-based match
-							sortSpec = plugin.sortSpecCache?.sortSpecByWildcard.folderMatch(folder.path)
+							sortSpec = plugin.sortSpecCache?.sortSpecByWildcard.folderMatch(folder.path, folder.name)
 							if (sortSpec?.defaultOrder === CustomSortOrder.standardObsidian) {
-								sortSpec = null // A folder subtree can be also explicitly excluded from custom sorting plugin
+								sortSpec = null // A folder is explicitly excluded from custom sorting plugin
 							}
 						}
 						if (sortSpec) {