Handle covert leaves differently

src/boxes.ts

@@ -46,7 +46,7 @@ function skipFree(tree: Tree): Tree {
 
 function words(tree: Tree): string {
 	if ('word' in tree) {
-		if (tree.word === 'covert' || tree.word === 'functional') {
+		if (tree.word.covert) {
 			return '';
 		} else {
 			return tree.word.text;
@@ -91,7 +91,7 @@ function boxifyClause(tree: Tree): BoxClause {
 	if (!('left' in cp)) throw new Error('bad CP?');
 	const c = cp.left;
 	if (!('word' in c)) throw new Error('C without word?');
-	if (c.word !== 'covert' && c.word !== 'functional') {
+	if (!c.word.covert) {
 		complementizer = c.word.text;
 	}
 	for (let node = cp.right; ; ) {
@@ -149,7 +149,7 @@ export function boxify(tree: Tree): BoxSentence {
 	const sa = tree.right;
 	if (sa.label !== 'SA') throw new Error('SAP without SA?');
 	if (!('word' in sa)) throw new Error('SA without word?');
-	if (sa.word !== 'covert' && sa.word !== 'functional') {
+	if (!sa.word.covert) {
 		speechAct = sa.word.text;
 	}
 	const cp = tree.left;

src/compact.ts

@@ -1,7 +1,7 @@
 import { Branch, Leaf, Tree, nodeType } from './tree';
 
 function isCovert(tree: Tree): boolean {
-	return 'word' in tree && typeof tree.word === 'string';
+	return 'word' in tree && tree.word.covert;
 }
 
 export function compact(tree: Tree): Tree {

src/draw-tree.ts

@@ -50,15 +50,9 @@ export function placeLeaf(
 	ctx: CanvasRenderingContext2D,
 	leaf: Leaf | (Leaf & { denotation: Expr | null }),
 ): PlacedLeaf {
-	const gloss =
-		typeof leaf.word === 'string' ? undefined : leaf.word.entry?.gloss;
+	const gloss = leaf.word.covert ? undefined : leaf.word.entry?.gloss;
 	const label = getLabel(leaf);
-	const word =
-		leaf.word === 'functional'
-			? undefined
-			: leaf.word === 'covert'
-			? '∅'
-			: leaf.word.text;
+	const word = leaf.word.covert ? leaf.word.value : leaf.word.text;
 	const denotation =
 		'denotation' in leaf && leaf.denotation !== null
 			? toPlainText(leaf.denotation)

src/english.ts

@@ -13,8 +13,7 @@ function leafText(tree: Tree): string {
 	if (!('word' in tree)) {
 		throw new Error('Unexpected non-leaf ' + tree.label);
 	}
-	if (tree.word === 'covert') return '';
-	if (tree.word === 'functional') return '';
+	if (tree.word.covert) return '';
 	return tree.word.text;
 }
 
@@ -48,7 +47,7 @@ function verbToEnglish(tree: Tree): string {
 }
 
 function serialToEnglish(serial: Tree): string {
-	if ('word' in serial && serial.word === 'covert') return '';
+	if ('word' in serial && serial.word.covert) return '';
 	if (serial.label !== '*Serial') throw new Error('non-*Serial serial');
 	if (!('children' in serial)) throw new Error('non-Rose serial');
 	return serial.children.map(x => verbToEnglish(x)).join('-');
@@ -364,7 +363,7 @@ function branchToEnglish(tree: Branch<Tree>): Constituent {
 			{ she: 'necessarily', ao: 'would', daı: 'possibly', ea: 'could' }[
 				bare(leafText(modal))
 			] ?? '?';
-		if (c.word === 'covert' || c.word === 'functional') {
+		if (c.word.covert) {
 			return { text: eng };
 		} else {
 			return {

src/grammar.ts

@@ -45,7 +45,6 @@ const {
 	makeAdjunctPT,
 	makeBranch,
 	makeBranchCovertLeft,
-	makeBranchFunctionalLeft,
 	makeConn,
     makeCovertLeaf,
 	makeLeaf,
@@ -110,7 +109,7 @@ const grammar: Grammar = {
     {"name": "DP", "symbols": ["D", "nP"], "postprocess": makeBranch('DP')},
     {"name": "DP", "symbols": ["Focus", "DP"], "postprocess": makeBranch('FocusP')},
     {"name": "nP", "symbols": ["nP", "CPrel"], "postprocess": makeBranch('nP')},
-    {"name": "nP", "symbols": ["CPdet"], "postprocess": makeBranchFunctionalLeft('nP', 'n')},
+    {"name": "nP", "symbols": ["CPdet"], "postprocess": makeBranchCovertLeft('nP', 'n')},
     {"name": "Clause", "symbols": ["term", "Bi", "Clause"], "postprocess": make3L('TopicP', "Topic'")},
     {"name": "Clause", "symbols": ["MTP"], "postprocess": id},
     {"name": "Clause", "symbols": ["DP", "Na", "CPrelna"], "postprocess": make3L('𝘷P', "𝘷'")},

src/latex.ts

@@ -26,10 +26,7 @@ export function toLatex(tree: Tree | DTree): string {
 		const children = tree.children.map(toLatex).join(' ');
 		return `[${label} ${children}]`;
 	} else {
-		if (tree.word === 'functional') {
-			return `[${label}]`;
-		}
-		if (tree.word === 'covert') {
+		if (tree.word.covert) {
 			return `[${label} [$\\varnothing$]]`;
 		}
 

src/semantics/denote.ts

@@ -1,5 +1,5 @@
 import { VerbEntry } from '../dictionary';
-import { Branch, Leaf, StrictTree, Word } from '../tree';
+import { Branch, CovertValue, Leaf, StrictTree, Word } from '../tree';
 import {
 	after,
 	afterNear,
@@ -351,10 +351,19 @@ const littleVAgent = λ('e', ['s'], c =>
 // λ𝘗. 𝘗
 const na = λ(['e', 't'], [], c => v(0, c));
 
-function denoteLittleV(toaq: string | null): Expr {
-	switch (toaq) {
-		case null:
+function denoteCovertLittleV(value: CovertValue): Expr | null {
+	switch (value) {
+		case 'CAUSE':
 			return littleVAgent;
+		case 'BE':
+			return null;
+		default:
+			throw new Error(`Unrecognized 𝘷: ${value}`);
+	}
+}
+
+function denoteOvertLittleV(toaq: string): Expr {
+	switch (toaq) {
 		case 'nä':
 			return na;
 		default:
@@ -408,16 +417,14 @@ function denoteLeaf(leaf: Leaf, cCommand: StrictTree | null): DTree {
 	let bindings = noBindings;
 
 	if (leaf.label === 'V') {
-		if (typeof leaf.word === 'string') throw new Error();
+		if (leaf.word.covert) throw new Error('covert V');
 		const entry = leaf.word.entry;
 		if (!entry) throw new Error();
 		if (entry.type !== 'predicate') throw new Error();
 
 		denotation = denoteVerb(entry.toaq, entry.frame.split(' ').length);
 	} else if (leaf.label === 'DP') {
-		if (leaf.word === 'functional') {
-			throw new Error('Functional DP');
-		} else if (leaf.word === 'covert') {
+		if (leaf.word.covert) {
 			denotation = hoa;
 			bindings = covertHoaBindings;
 		} else if (leaf.word.entry === undefined) {
@@ -517,23 +524,16 @@ function denoteLeaf(leaf: Leaf, cCommand: StrictTree | null): DTree {
 			covertResumptive: binding,
 		};
 	} else if (leaf.label === '𝘷') {
-		let toaq: string | null;
-		if (typeof leaf.word === 'string') {
-			toaq = null;
+		if (leaf.word.covert) {
+			denotation = denoteCovertLittleV(leaf.word.value);
 		} else if (leaf.word.entry === undefined) {
 			throw new Error(`Unrecognized 𝘷: ${leaf.word.text}`);
 		} else {
-			toaq = leaf.word.entry.toaq;
+			denotation = denoteOvertLittleV(leaf.word.entry.toaq);
 		}
-
-		denotation = denoteLittleV(toaq);
-	} else if (leaf.label === '𝘷0') {
-		denotation = null;
 	} else if (leaf.label === 'Asp') {
 		let toaq: string;
-		if (leaf.word === 'functional') {
-			throw new Error('Functional Asp');
-		} else if (leaf.word === 'covert') {
+		if (leaf.word.covert) {
 			toaq = 'tam';
 		} else if (leaf.word.entry === undefined) {
 			throw new Error(`Unrecognized Asp: ${leaf.word.text}`);
@@ -543,9 +543,7 @@ function denoteLeaf(leaf: Leaf, cCommand: StrictTree | null): DTree {
 
 		denotation = denoteAspect(toaq);
 	} else if (leaf.label === 'T') {
-		if (leaf.word === 'functional') {
-			throw new Error('Functional T');
-		} else if (leaf.word === 'covert') {
+		if (leaf.word.covert) {
 			denotation = defaultTense;
 		} else if (leaf.word.entry === undefined) {
 			throw new Error(`Unrecognized T: ${leaf.word.text}`);
@@ -556,9 +554,7 @@ function denoteLeaf(leaf: Leaf, cCommand: StrictTree | null): DTree {
 		denotation = null;
 	} else if (leaf.label === 'SA') {
 		let toaq: string;
-		if (leaf.word === 'functional') {
-			throw new Error('Functional SA');
-		} else if (leaf.word === 'covert') {
+		if (leaf.word.covert) {
 			toaq = 'da'; // TODO: covert móq
 		} else if (leaf.word.entry === undefined) {
 			throw new Error(`Unrecognized SA: ${leaf.word.text}`);
@@ -771,7 +767,6 @@ function getCompositionRule(left: DTree, right: DTree): CompositionRule {
 	switch (left.label) {
 		case 'V':
 		case 'Asp':
-		case '𝘷0':
 		case 'n':
 			return functionalApplication;
 		case 'T':

src/serial.ts

@@ -1,13 +1,12 @@
-import { Branch, Label, Tree } from './tree';
+import { Branch, Label, Tree, makeNull } from './tree';
 
 const arityPreservingVerbPrefixes: Label[] = ['buP', 'muP', 'buqP', 'geP'];
 
-const pro: Tree = { label: 'DP', word: 'covert' };
+const pro: Tree = { label: 'DP', word: { covert: true, value: 'PRO' } };
 
 export function getFrame(verb: Tree): string {
 	if ('word' in verb) {
-		if (verb.word === 'covert') throw new Error('covert verb?');
-		if (verb.word === 'functional') throw new Error('functional verb?');
+		if (verb.word.covert) throw new Error('covert verb?');
 		if (verb.word.entry?.type === 'predicate') {
 			return verb.word.entry.frame;
 		} else {
@@ -42,7 +41,7 @@ function serialTovP(verbs: Tree[], args: Tree[]): Tree {
 		if (arity === 1) {
 			return {
 				label: '𝘷P',
-				left: { label: '𝘷0', word: 'functional' },
+				left: { label: '𝘷', word: { covert: true, value: 'BE' } },
 				right: { label: 'VP', left: verbs[0], right: args[0] },
 			};
 		} else if (arity === 2) {
@@ -51,7 +50,7 @@ function serialTovP(verbs: Tree[], args: Tree[]): Tree {
 				left: args[0],
 				right: {
 					label: "𝘷'",
-					left: { label: '𝘷', word: 'functional' },
+					left: { label: '𝘷', word: { covert: true, value: 'CAUSE' } },
 					right: { label: 'VP', left: verbs[0], right: args[1] },
 				},
 			};
@@ -61,7 +60,7 @@ function serialTovP(verbs: Tree[], args: Tree[]): Tree {
 				left: args[0],
 				right: {
 					label: "𝘷'",
-					left: { label: '𝘷', word: 'functional' },
+					left: { label: '𝘷', word: { covert: true, value: 'CAUSE' } },
 					right: {
 						label: 'VP',
 						left: args[1],
@@ -95,7 +94,7 @@ function serialTovP(verbs: Tree[], args: Tree[]): Tree {
 		if (arity === 1) {
 			return {
 				label: '𝘷P',
-				left: { label: '𝘷0', word: 'functional' },
+				left: { label: '𝘷', word: { covert: true, value: 'BE' } },
 				right: { label: 'VP', left: verbs[0], right: inner },
 			};
 		} else if (arity === 2) {
@@ -104,7 +103,7 @@ function serialTovP(verbs: Tree[], args: Tree[]): Tree {
 				left: args[0],
 				right: {
 					label: "𝘷'",
-					left: { label: '𝘷', word: 'functional' },
+					left: { label: '𝘷', word: { covert: true, value: 'CAUSE' } },
 					right: { label: 'VP', left: verbs[0], right: inner },
 				},
 			};
@@ -114,7 +113,7 @@ function serialTovP(verbs: Tree[], args: Tree[]): Tree {
 				left: args[0],
 				right: {
 					label: "𝘷'",
-					left: { label: '𝘷', word: 'functional' },
+					left: { label: '𝘷', word: { covert: true, value: 'CAUSE' } },
 					right: {
 						label: 'VP',
 						left: args[1],
@@ -134,21 +133,18 @@ function attachAdjective(VP: Tree, vP: Tree): Tree {
 		left: VP,
 		right: {
 			label: 'aP',
-			left: {
-				label: 'a',
-				word: 'covert', // TODO ki
-			},
+			left: makeNull('a'), // TODO ki-
 			right: {
 				// TODO: oh god, adjectives can have T and Asp?
 				// needs rework in nearley grammar
 				label: 'CPrel',
-				left: { label: 'C', word: 'covert' },
+				left: makeNull('C'),
 				right: {
 					label: 'TP',
-					left: { label: 'T', word: 'covert' },
+					left: makeNull('T'),
 					right: {
 						label: 'AspP',
-						left: { label: 'Asp', word: 'covert' },
+						left: makeNull('Asp'),
 						right: vP,
 					},
 				},

src/textual-tree.ts

@@ -2,12 +2,7 @@ import { Tree } from './tree';
 
 function ttree_converted(data: Tree): { label: string; branches: any } {
 	if ('word' in data) {
-		const b =
-			data.word === 'covert'
-				? '∅'
-				: data.word === 'functional'
-				? '🅵'
-				: data.word.text.toLowerCase();
+		const b = data.word.covert ? data.word.value : data.word.text.toLowerCase();
 		return { label: data.label, branches: [b] };
 	} else if ('left' in data) {
 		return {

src/toaq.ne

@@ -8,7 +8,6 @@ const {
 	makeAdjunctPT,
 	makeBranch,
 	makeBranchCovertLeft,
-	makeBranchFunctionalLeft,
 	makeConn,
     makeCovertLeaf,
 	makeLeaf,
@@ -61,7 +60,7 @@ DP -> Focus DP {% makeBranch('FocusP') %}
 # (sá) ꝡë hao
 nP -> nP CPrel {% makeBranch('nP') %}
 # (sá) ∅ hao
-nP -> CPdet {% makeBranchFunctionalLeft('nP', 'n') %}
+nP -> CPdet {% makeBranchCovertLeft('nP', 'n') %}
 
 # ní bï pu hao
 Clause -> term Bi Clause {% make3L('TopicP', "Topic'") %}