From 869c5d094b54ae481228ad1777598fed3728fe2e Mon Sep 17 00:00:00 2001
From: "John J. Camilleri" <john@digitalgrammars.com>
Date: Tue, 5 Oct 2021 13:39:51 +0200
Subject: [PATCH] Implement categoryProbability, functionProbability,
 functionIsConstructor, functionsByCategory

---
 src/runtime/javascript/index.ts            | 45 ++++++++++++++++++++++
 src/runtime/javascript/tests/basic.test.ts | 45 ++++++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/src/runtime/javascript/index.ts b/src/runtime/javascript/index.ts
index 702b666c3..724ea5963 100644
--- a/src/runtime/javascript/index.ts
+++ b/src/runtime/javascript/index.ts
@@ -204,6 +204,51 @@ export class PGFGrammar {
     return funs
   }
 
+  categoryProbability (cat: string): number | undefined {
+    const catname = PgfText_FromString(cat)
+    const err = new PgfExn
+    const prob = runtime.pgf_category_prob(this.db, this.revision.deref(), catname, err.ref())
+    handleError(err)
+    if (prob === Infinity) {
+      return undefined
+    } else {
+      return prob
+    }
+  }
+
+  functionProbability (fun: string): number | undefined {
+    const funname = PgfText_FromString(fun)
+    const err = new PgfExn
+    const prob = runtime.pgf_function_prob(this.db, this.revision.deref(), funname, err.ref())
+    handleError(err)
+    if (prob === Infinity) {
+      return undefined
+    } else {
+      return prob
+    }
+  }
+
+  functionIsConstructor (fun: string): boolean {
+    const funname = PgfText_FromString(fun)
+    const err = new PgfExn
+    const isCon = runtime.pgf_function_is_constructor(this.db, this.revision.deref(), funname, err.ref())
+    handleError(err)
+    return Boolean(isCon)
+  }
+
+  functionsByCategory (cat: string): string[] {
+    const catname = PgfText_FromString(cat)
+    const funs: string[] = []
+    const callback = ffi.Callback(ref.types.void, [ PgfItorPtr, PgfTextPtr, voidPtr, PgfExnPtr ],
+      function (self: Pointer<any>, key: Pointer<any>, value: Pointer<any>, err: Pointer<any>) { // eslint-disable-line @typescript-eslint/no-unused-vars
+        const k = PgfText_AsString(key)
+        funs.push(k)
+    })
+    const err = new PgfExn
+    runtime.pgf_iter_functions_by_cat(this.db, this.revision.deref(), catname, callback.ref() as Pointer<void>, err.ref())
+    handleError(err)
+    return funs
+  }
 }
 
 // ----------------------------------------------------------------------------
diff --git a/src/runtime/javascript/tests/basic.test.ts b/src/runtime/javascript/tests/basic.test.ts
index f975b1d24..497419ede 100644
--- a/src/runtime/javascript/tests/basic.test.ts
+++ b/src/runtime/javascript/tests/basic.test.ts
@@ -160,4 +160,49 @@ describe('abstract syntax', () => {
   test('functions', () => {
     expect(gr.getFunctions()).toEqual(['c','ind','s','z'])
   })
+
+  describe('function is constructor', () => {
+    test('s', () => {
+      expect(gr.functionIsConstructor('s')).toBe(true)
+    })
+    test('z', () => {
+      expect(gr.functionIsConstructor('z')).toBe(true)
+    })
+    test('c', () => {
+      expect(gr.functionIsConstructor('c')).toBe(true)
+    })
+    test('ind', () => {
+      expect(gr.functionIsConstructor('ind')).toBe(false)
+    })
+  })
+
+  describe('functions by category', () => {
+    test('N', () => {
+      expect(gr.functionsByCategory('N')).toEqual(['s','z'])
+    })
+    test('S', () => {
+      expect(gr.functionsByCategory('S')).toEqual(['c'])
+    })
+    test('X', () => {
+      expect(gr.functionsByCategory('X')).toEqual([])
+    })
+  })
+
+  describe('probabilities', () => {
+    test.skip('category existing', () => {
+      expect(gr.categoryProbability('S')).toBeDefined()
+    })
+
+    test('category non-existent', () => {
+      expect(gr.categoryProbability('NP')).toBeUndefined()
+    })
+
+    test('function existing', () => {
+      expect(gr.functionProbability('c')).toBeDefined() // returns -0 (!)
+    })
+
+    test('function non-existent', () => {
+      expect(gr.functionProbability('mkC')).toBeUndefined()
+    })
+  })
 })