From 2dbe84c95da65504172a68ad974174b9c5bd48b7 Mon Sep 17 00:00:00 2001
From: Danielo Rodriguez <rdanielo@gmail.com>
Date: Thu, 19 Dec 2024 19:58:30 +0100
Subject: [PATCH 1/3] feat(parser): add support for parsing transformations

---
 src/core/template/templateParser.test.ts      | 137 +++++++++++-------
 src/core/template/templateParser.ts           |  48 ++++--
 src/core/template/templateSchema.ts           |  29 +++-
 .../components/Form/MarkdownBlock.svelte      |   3 +-
 4 files changed, 147 insertions(+), 70 deletions(-)

diff --git a/src/core/template/templateParser.test.ts b/src/core/template/templateParser.test.ts
index 7a00ac59..b33a1ba0 100644
--- a/src/core/template/templateParser.test.ts
+++ b/src/core/template/templateParser.test.ts
@@ -1,83 +1,112 @@
-import { parseTemplate, anythingUntilOpenOrEOF, executeTemplate } from "./templateParser";
-import * as S from 'parser-ts/string'
-import * as E from "fp-ts/Either";
 import { pipe, tap } from "@std";
+import * as E from "fp-ts/Either";
 import { stringifyYaml } from "obsidian";
+import * as S from "parser-ts/string";
+import { anythingUntilOpenOrEOF, executeTemplate, parseTemplate } from "./templateParser";
 
 const inspect = (val: unknown) => {
     console.dir(val, { depth: 10 });
     return val;
-}
+};
 const logError = E.mapLeft(console.log);
 
 describe("parseTemplate", () => {
     it.skip("test", () => {
         pipe(
+            // stupid prettier
             S.run("al{nam{{e}}")(anythingUntilOpenOrEOF),
-            inspect)
+            inspect,
+        );
     });
     it("should parse a single identifier template", () => {
         const template = "{{name}}";
         const result = parseTemplate(template);
         expect(result).toEqual(E.of([{ _tag: "variable", value: "name" }]));
-
     });
     it("templates can start with an identifier", () => {
         const template = "{{name}} is a name";
         const result = parseTemplate(template);
-        expect(result).toEqual(E.of([
-            { _tag: "variable", value: "name" },
-            { _tag: "text", value: " is a name" },
-        ]));
+        expect(result).toEqual(
+            E.of([
+                { _tag: "variable", value: "name" },
+                { _tag: "text", value: " is a name" },
+            ]),
+        );
     });
     it("should parse a valid template", () => {
         const template = "Hello, {{name}}!";
         const result = parseTemplate(template);
         logError(result);
-        expect(result).toEqual(E.of(
-            [
+        expect(result).toEqual(
+            E.of([
                 { _tag: "text", value: "Hello, " },
                 { _tag: "variable", value: "name" },
                 { _tag: "text", value: "!" },
-            ],
-        ));
+            ]),
+        );
     });
     it("should parse a valid template with several variables", () => {
         const template = "Hello, {{name}}! You are {{age}} years old.";
         const result = parseTemplate(template);
         logError(result);
-        expect(result).toEqual(E.of(
-            [
+        expect(result).toEqual(
+            E.of([
                 { _tag: "text", value: "Hello, " },
                 { _tag: "variable", value: "name" },
                 { _tag: "text", value: "! You are " },
                 { _tag: "variable", value: "age" },
                 { _tag: "text", value: " years old." },
-            ],
-        ));
+            ]),
+        );
+    });
+
+    it("should parse a variables with transformations", () => {
+        const template = "Hello, {{name|uppercase}}! You are {{age|stringify}} years old.";
+        const result = parseTemplate(template);
+        logError(result);
+        expect(result).toEqual(
+            E.of([
+                { _tag: "text", value: "Hello, " },
+                { _tag: "variable", value: "name", transformation: "upper" },
+                { _tag: "text", value: "! You are " },
+                { _tag: "variable", value: "age", transformation: "stringify" },
+                { _tag: "text", value: " years old." },
+            ]),
+        );
+    });
+
+    it("should silently ignore invalid transformations", () => {
+        const template = "Hello, {{name|invalid}}! You are {{age|stringify}} years old.";
+        const result = parseTemplate(template);
+        logError(result);
+        expect(result).toEqual(
+            E.of([
+                { _tag: "text", value: "Hello, " },
+                { _tag: "variable", value: "name" },
+                { _tag: "text", value: "! You are " },
+                { _tag: "variable", value: "age", transformation: "stringify" },
+                { _tag: "text", value: " years old." },
+            ]),
+        );
     });
 
     it("should allow single braces in a template", () => {
         const template = "This is code {bla}";
         const result = parseTemplate(template);
         logError(result);
-        expect(result).toEqual(E.of(
-            [
-                { _tag: "text", value: "This is code {bla}" },
-            ],
-        ));
-    })
+        expect(result).toEqual(E.of([{ _tag: "text", value: "This is code {bla}" }]));
+    });
     it("should allow single braces in a template even if it has variables", () => {
         const template = "This is code {bla} {{name}}";
         const result = parseTemplate(template);
         logError(result);
-        expect(result).toEqual(E.of(
-            [
+        expect(result).toEqual(
+            E.of([
                 { _tag: "text", value: "This is code {bla} " },
                 { _tag: "variable", value: "name" },
-            ],
-        ));
-    })
+            ]),
+        );
+    });
 
     it.skip("should return a parse error for an invalid template", () => {
         const template = "Hey, {{name}!";
@@ -96,59 +125,59 @@ describe("parseTemplate", () => {
         const template = "Hey, {{ name }}!";
         const result = parseTemplate(template);
         logError(result);
-        expect(result).toEqual(E.of(
-            [
+        expect(result).toEqual(
+            E.of([
                 { _tag: "text", value: "Hey, " },
                 { _tag: "variable", value: "name" },
                 { _tag: "text", value: "!" },
-            ],
-        ));
-    })
+            ]),
+        );
+    });
     it("should parse a frontmatter command", () => {
         const template = "{#frontmatter#}";
         const result = parseTemplate(template);
         expect(result).toEqual(E.of([{ _tag: "frontmatter-command", pick: [], omit: [] }]));
-    })
+    });
 
     it("should parse a frontmatter command that includes spaces", () => {
         const template = "{# frontmatter #}";
         const result = parseTemplate(template);
         expect(result).toEqual(E.of([{ _tag: "frontmatter-command", pick: [], omit: [] }]));
-    })
+    });
     it("should parse a frontmatter command with pick values", () => {
         const template = "{# frontmatter pick: name,age #}";
         const result = parseTemplate(template);
-        expect(result).toEqual(E.of([{ _tag: "frontmatter-command", pick: ['name', 'age'], omit: [] }]));
-    })
+        expect(result).toEqual(
+            E.of([{ _tag: "frontmatter-command", pick: ["name", "age"], omit: [] }]),
+        );
+    });
 
     it("should parse a frontmatter command with pick values that can be separated by spaces", () => {
         const template = "{# frontmatter pick: name, age #}";
         const result = parseTemplate(template);
-        expect(result).toEqual(E.of([{ _tag: "frontmatter-command", pick: ['name', 'age'], omit: [] }]));
-    })
+        expect(result).toEqual(
+            E.of([{ _tag: "frontmatter-command", pick: ["name", "age"], omit: [] }]),
+        );
+    });
 
     it("Should properly execute a template with a frontmatter command", () => {
         const template = "{# frontmatter #}";
         const parsed = parseTemplate(template);
         const result = pipe(
             parsed,
-            E.map((parsedTemplate) =>
-                executeTemplate(parsedTemplate, { name: 'John', age: 18 })
-            ),
-            E.map(tap('executed')),
-        )
-        expect(result).toEqual(E.of(stringifyYaml({ name: 'John', age: 18 })))
-    })
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of(stringifyYaml({ name: "John", age: 18 })));
+    });
     it("Should properly execute a template with a frontmatter command that specifies a pick", () => {
         const template = "{# frontmatter pick: name #}";
         const parsed = parseTemplate(template);
         const result = pipe(
             parsed,
-            E.map((parsedTemplate) =>
-                executeTemplate(parsedTemplate, { name: 'John', age: 18 })
-            ),
-            E.map(tap('executed')),
-        )
-        expect(result).toEqual(E.of(stringifyYaml({ name: 'John' })))
-    })
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of(stringifyYaml({ name: "John" })));
+    });
 });
diff --git a/src/core/template/templateParser.ts b/src/core/template/templateParser.ts
index e47c400a..99225f38 100644
--- a/src/core/template/templateParser.ts
+++ b/src/core/template/templateParser.ts
@@ -1,23 +1,29 @@
-import { Either, O, pipe } from "@std";
+import { Either, O, parse, pipe } from "@std";
 import * as A from "fp-ts/Array";
 import * as E from "fp-ts/Either";
 import * as R from "fp-ts/Record";
-import { absurd, identity } from "fp-ts/function";
+import { absurd, constUndefined, identity } from "fp-ts/function";
 import * as St from "fp-ts/string";
 import { stringifyYaml } from "obsidian";
 import * as P from "parser-ts/Parser";
 import * as C from "parser-ts/char";
 import * as S from "parser-ts/string";
 import { ModalFormData } from "../FormResult";
-import type { FrontmatterCommand, TemplateText, TemplateVariable } from "./templateSchema";
+import {
+    transformations,
+    type FrontmatterCommand,
+    type TemplateText,
+    type TemplateVariable,
+    type Transformations,
+} from "./templateSchema";
 type Token = TemplateText | TemplateVariable | FrontmatterCommand;
 export type ParsedTemplate = Token[];
 
 function TemplateText(value: string): TemplateText {
     return { _tag: "text", value };
 }
-function TemplateVariable(value: string): TemplateVariable {
-    return { _tag: "variable", value };
+function TemplateVariable(value: string, transformation?: Transformations): TemplateVariable {
+    return { _tag: "variable", value, transformation };
 }
 
 function FrontmatterCommand(pick: string[] = [], omit: string[] = []): FrontmatterCommand {
@@ -36,10 +42,30 @@ const EofStr = pipe(
 const open = S.fold([S.string("{{"), S.spaces]);
 const close = P.expected(S.fold([S.spaces, S.string("}}")]), 'closing variable tag: "}}"');
 const identifier = S.many1(C.alphanum);
+const transformation = pipe(
+    // dam prettier
+    S.fold([S.string("|"), S.spaces]),
+    P.apSecond(identifier),
+    P.map((x) => {
+        return pipe(
+            parse(transformations, x),
+            E.fold(constUndefined, (x) => x),
+        );
+    }),
+);
+
 const templateIdentifier: TokenParser = pipe(
-    identifier,
+    identifier, // First, we parse the variable name
+    // chain takes a function that accepts the result of the previous parser and returns a new parser
+    P.chain((value) =>
+        pipe(
+            // Within this pipe we build a parser of Parser<string, TemplateVariable> also using the value of the previous parser
+            P.optional(transformation),
+            P.map((trans) => TemplateVariable(value, O.toUndefined(trans))),
+        ),
+    ),
+    // finally we wrap the resulting parser in between the open and close strings
     P.between(open, close),
-    P.map(TemplateVariable),
 );
 
 // === Command Parser ===
@@ -148,7 +174,7 @@ function tokenToString(token: Token): string {
         case "text":
             return token.value;
         case "variable":
-            return `{{${token.value}}}`;
+            return `{{${token.value}${token.transformation ? `|${token.transformation}` : ""}}}`;
         case "frontmatter-command":
             return `{{# frontmatter pick: ${token.pick.join(", ")}, omit: ${token.omit.join(
                 ", ",
@@ -160,7 +186,7 @@ function tokenToString(token: Token): string {
 
 function matchToken<T>(
     onText: (value: string) => T,
-    onVariable: (variable: string) => T,
+    onVariable: (variable: string, transformation?: string) => T,
     onCommand: (command: FrontmatterCommand) => T,
 ) {
     return (token: Token): T => {
@@ -168,7 +194,7 @@ function matchToken<T>(
             case "text":
                 return onText(token.value);
             case "variable":
-                return onVariable(token.value);
+                return onVariable(token.value, token.transformation);
             case "frontmatter-command":
                 return onCommand(token);
             default:
@@ -213,7 +239,7 @@ export function executeTemplate(parsedTemplate: ParsedTemplate, formData: ModalF
         A.filterMap(
             matchToken(
                 O.some,
-                (key) => O.fromNullable(formData[key]),
+                (key, transformation) => O.fromNullable(formData[key]),
                 (command) =>
                     pipe(
                         //prettier
diff --git a/src/core/template/templateSchema.ts b/src/core/template/templateSchema.ts
index a43eb8f1..a7209b69 100644
--- a/src/core/template/templateSchema.ts
+++ b/src/core/template/templateSchema.ts
@@ -1,13 +1,35 @@
-import { Output, array, literal, object, string, union } from "valibot";
+import {
+    Output,
+    array,
+    enumType,
+    literal,
+    object,
+    optional,
+    string,
+    transform,
+    union,
+} from "valibot";
 
 const TemplateTextSchema = object({
     _tag: literal("text"),
     value: string(),
 });
 
+const upper = transform(enumType(["upper", "uppercase"]), (_) => "upper" as const);
+
+export const transformations = union([
+    upper,
+    literal("lower"),
+    literal("trim"),
+    literal("stringify"),
+]);
+
+export type Transformations = Output<typeof transformations>;
+
 const TemplateVariableSchema = object({
     _tag: literal("variable"),
     value: string(),
+    transformation: optional(transformations),
 });
 
 const FrontmatterCommandSchema = object({
@@ -16,8 +38,9 @@ const FrontmatterCommandSchema = object({
     omit: array(string()),
 });
 
-export const ParsedTemplateSchema = array(union([TemplateTextSchema, TemplateVariableSchema, FrontmatterCommandSchema]))
-
+export const ParsedTemplateSchema = array(
+    union([TemplateTextSchema, TemplateVariableSchema, FrontmatterCommandSchema]),
+);
 
 export type TemplateText = Output<typeof TemplateTextSchema>;
 export type TemplateVariable = Output<typeof TemplateVariableSchema>;
diff --git a/src/views/components/Form/MarkdownBlock.svelte b/src/views/components/Form/MarkdownBlock.svelte
index f7d1d614..423f26e5 100644
--- a/src/views/components/Form/MarkdownBlock.svelte
+++ b/src/views/components/Form/MarkdownBlock.svelte
@@ -1,7 +1,6 @@
 <script lang="ts">
-    import { parseFunctionBody, pipe } from "@std";
+    import { parseFunctionBody, pipe, TE } from "@std";
     import * as R from "fp-ts/Record";
-    import * as TE from "fp-ts/TaskEither";
     import { App, Component, MarkdownRenderer } from "obsidian";
     import { input } from "src/core";
     import { FieldValue, FormEngine } from "src/store/formEngine";

From 7552a2a6095ff1fd51c1b0010abfc08edc53ffa3 Mon Sep 17 00:00:00 2001
From: Danielo Rodriguez <rdanielo@gmail.com>
Date: Thu, 19 Dec 2024 21:35:36 +0100
Subject: [PATCH 2/3] feat(template): execute transformations when applying
 templates

---
 .../.obsidian/plugins/modal-form/data.json    |  7 +-
 src/core/template/templateParser.test.ts      | 78 +++++++++++++++++++
 src/core/template/templateParser.ts           | 37 ++++++++-
 3 files changed, 115 insertions(+), 7 deletions(-)

diff --git a/EXAMPLE_VAULT/.obsidian/plugins/modal-form/data.json b/EXAMPLE_VAULT/.obsidian/plugins/modal-form/data.json
index 89ab684c..28fa6ad3 100644
--- a/EXAMPLE_VAULT/.obsidian/plugins/modal-form/data.json
+++ b/EXAMPLE_VAULT/.obsidian/plugins/modal-form/data.json
@@ -450,7 +450,6 @@
       ],
       "version": "1",
       "template": {
-        "createCommand": true,
         "parsedTemplate": [
           {
             "_tag": "text",
@@ -514,7 +513,8 @@
           },
           {
             "_tag": "variable",
-            "value": "dateOfBirth"
+            "value": "dateOfBirth",
+            "transformation": "stringify"
           },
           {
             "_tag": "text",
@@ -576,7 +576,8 @@
             "_tag": "text",
             "value": "\n\n---\n> Last modified: <% tp.file.last_modified_date(\"dddd, MMMM Do YYYY HH:mm:ss\") %>"
           }
-        ]
+        ],
+        "createCommand": true
       }
     }
   ]
diff --git a/src/core/template/templateParser.test.ts b/src/core/template/templateParser.test.ts
index b33a1ba0..c0895eb3 100644
--- a/src/core/template/templateParser.test.ts
+++ b/src/core/template/templateParser.test.ts
@@ -133,6 +133,84 @@ describe("parseTemplate", () => {
             ]),
         );
     });
+
+    it("should properly execute a template with transformations", () => {
+        const template = "Hello, {{name|upper}}! You are {{age|stringify}} years old.";
+        const parsed = parseTemplate(template);
+        const result = pipe(
+            parsed,
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of("Hello, JOHN! You are 18 years old."));
+    });
+
+    it("Should execute a template with lowercase transformations", () => {
+        const template = "Hello, {{name|lower}}! You are {{age}} years old.";
+        const parsed = parseTemplate(template);
+        const result = pipe(
+            parsed,
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of("Hello, john! You are 18 years old."));
+    });
+
+    it("Should execute a template with trim transformations", () => {
+        const template = "Hello, {{name|trim}}!";
+        const parsed = parseTemplate(template);
+        const result = pipe(
+            parsed,
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: " John ", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of("Hello, John!"));
+    });
+
+    it("Should execute a template with stringify transformations", () => {
+        const template = "Hello, {{name|stringify}}!";
+        const parsed = parseTemplate(template);
+        const result = pipe(
+            parsed,
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of('Hello, "John"!'));
+    });
+
+    it("Spaces around transformations should be ignored", () => {
+        const template = "Hello, {{name | stringify }}!";
+        const parsed = parseTemplate(template);
+        const result = pipe(
+            parsed,
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of('Hello, "John"!'));
+    });
+
+    it("Spaces around transformations AND variables should be ignored", () => {
+        const template = "Hello, {{ name | stringify }}!";
+        const parsed = parseTemplate(template);
+        const result = pipe(
+            parsed,
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of('Hello, "John"!'));
+    });
+
+    it("Should execute a template with no transformations", () => {
+        const template = "Hello, {{name}}! You are {{age}} years old.";
+        const parsed = parseTemplate(template);
+        const result = pipe(
+            parsed,
+            E.map((parsedTemplate) => executeTemplate(parsedTemplate, { name: "John", age: 18 })),
+            E.map(tap("executed")),
+        );
+        expect(result).toEqual(E.of("Hello, John! You are 18 years old."));
+    });
+
     it("should parse a frontmatter command", () => {
         const template = "{#frontmatter#}";
         const result = parseTemplate(template);
diff --git a/src/core/template/templateParser.ts b/src/core/template/templateParser.ts
index 99225f38..43a71f0c 100644
--- a/src/core/template/templateParser.ts
+++ b/src/core/template/templateParser.ts
@@ -8,7 +8,7 @@ import { stringifyYaml } from "obsidian";
 import * as P from "parser-ts/Parser";
 import * as C from "parser-ts/char";
 import * as S from "parser-ts/string";
-import { ModalFormData } from "../FormResult";
+import { ModalFormData, Val } from "../FormResult";
 import {
     transformations,
     type FrontmatterCommand,
@@ -44,7 +44,7 @@ const close = P.expected(S.fold([S.spaces, S.string("}}")]), 'closing variable t
 const identifier = S.many1(C.alphanum);
 const transformation = pipe(
     // dam prettier
-    S.fold([S.string("|"), S.spaces]),
+    S.fold([S.spaces, S.string("|"), S.spaces]),
     P.apSecond(identifier),
     P.map((x) => {
         return pipe(
@@ -141,6 +141,9 @@ export function parseTemplate(template: string): Either<string, ParsedTemplate>
     // return S.run(template)(P.many(Template))
 }
 
+/**
+ * Given a parsed template, returns a list of the variables used in the template
+ */
 export function templateVariables(parsedTemplate: ReturnType<typeof parseTemplate>): string[] {
     return pipe(
         parsedTemplate,
@@ -186,7 +189,7 @@ function tokenToString(token: Token): string {
 
 function matchToken<T>(
     onText: (value: string) => T,
-    onVariable: (variable: string, transformation?: string) => T,
+    onVariable: (variable: string, transformation?: Transformations) => T,
     onCommand: (command: FrontmatterCommand) => T,
 ) {
     return (token: Token): T => {
@@ -232,6 +235,28 @@ function asFrontmatterString(data: Record<string, unknown>) {
         );
 }
 
+function executeTransformation(
+    transformation: Transformations | undefined,
+): (value: Val) => string {
+    return (value) => {
+        if (transformation === undefined) {
+            return String(value);
+        }
+        switch (transformation) {
+            case "upper":
+                return String(value).toUpperCase();
+            case "lower":
+                return String(value).toLowerCase();
+            case "stringify":
+                return JSON.stringify(value);
+            case "trim":
+                return String(value).trim();
+            default:
+                return absurd(transformation);
+        }
+    };
+}
+
 export function executeTemplate(parsedTemplate: ParsedTemplate, formData: ModalFormData) {
     const toFrontmatter = asFrontmatterString(formData); // Build it upfront rater than on every call
     return pipe(
@@ -239,7 +264,11 @@ export function executeTemplate(parsedTemplate: ParsedTemplate, formData: ModalF
         A.filterMap(
             matchToken(
                 O.some,
-                (key, transformation) => O.fromNullable(formData[key]),
+                (key, transformation) =>
+                    pipe(
+                        O.fromNullable(formData[key]),
+                        O.map(executeTransformation(transformation)),
+                    ),
                 (command) =>
                     pipe(
                         //prettier

From 1421013b9470f65a8aa0c769c43ec18e9a75232c Mon Sep 17 00:00:00 2001
From: Danielo Rodriguez <rdanielo@gmail.com>
Date: Thu, 19 Dec 2024 22:45:06 +0100
Subject: [PATCH 3/3] docs: document transformations in templates

---
 docs/templates.md | 105 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 101 insertions(+), 4 deletions(-)

diff --git a/docs/templates.md b/docs/templates.md
index 536ff8ac..0720b56d 100644
--- a/docs/templates.md
+++ b/docs/templates.md
@@ -20,6 +20,103 @@ Variables are placeholders that get replaced with form field values. The variabl
 Hello {{name}}! Your favorite color is {{color}}.
 ```
 
+#### Basic Variable Syntax
+
+- **Variable Declaration**:
+
+  ```plaintext
+  {{ variableName }}
+  ```
+
+  Example:
+
+  ```plaintext
+  {{ name }}
+  ```
+
+Note that spaces around the variable name are ignored, allowing for flexibility in formatting.
+
+```plaintext
+This is a {{variableName}}. And this is also a valid {{ variableName }}
+```
+
+#### Variable with Transformations
+
+- **Transformation Syntax**: You can apply transformations to a variable by using a pipe `|` followed by the transformation name.
+  
+  ```plaintext
+  {{ variableName | transformation }}
+  ```
+
+  Example:
+
+  ```plaintext
+  {{ name | trim }}
+  ```
+
+### Supported Transformations
+
+The following transformations can be applied to variables:
+
+1. **`upper`**: Converts the variable's value to uppercase.
+   - Usage:
+
+     ```plaintext
+     {{ name | upper }}
+     ```
+
+2. **`lower`**: Converts the variable's value to lowercase.
+   - Usage:
+
+     ```plaintext
+     {{ name | lower }}
+     ```
+
+3. **`trim`**: Removes whitespace from both ends of the variable's value.
+   - Usage:
+
+     ```plaintext
+     {{ name | trim }}
+     ```
+
+4. **`stringify`**: Converts the variable's value to a JSON string.
+   - Usage:
+
+     ```plaintext
+     {{ name | stringify }}
+     ```
+
+### Example Templates
+
+Here are some examples of how to use the new template syntax:
+
+- **Single Variable**:
+
+  ```plaintext
+  Hello, {{ name }}!
+  ```
+
+- **Variable with Transformation**:
+
+  ```plaintext
+  Hello, {{ name | upper }}!
+  ```
+
+- **Multiple Variables with Transformations**:
+
+  ```plaintext
+  Hello, {{ name | trim }}! You are {{ age }} years old.
+  ```
+
+### Notes
+
+- If an invalid transformation is specified, it will be silently ignored, and the variable will be processed without transformation.
+- Spaces around the transformation operator (`|`) are ignored, allowing for flexibility in formatting:
+
+  ```plaintext
+  {{ name | trim }} or {{ name|trim }} are both valid.
+  ```
+
 ### Available Commands
 
 #### Frontmatter Command
@@ -27,7 +124,7 @@ Hello {{name}}! Your favorite color is {{color}}.
 The frontmatter command controls which form fields appear in the YAML frontmatter section of your note:
 
 ```
-{{# frontmatter pick: title, tags #}}
+{# frontmatter pick: title, tags #}
 ```
 
 Options:
@@ -38,13 +135,13 @@ Options:
 You can combine both options:
 
 ```
-{{# frontmatter pick: title, tags, date omit: draft #}}
+{# frontmatter pick: title, tags, date omit: draft #}
 ```
 
 If no options are specified, all form fields will be included in the frontmatter:
 
 ```
-{{# frontmatter #}}
+{# frontmatter #}
 ```
 
 ## Templater Support
@@ -67,7 +164,7 @@ Note: This feature is only available if you have the Templater plugin installed
 Here's a complete template example that combines variables and frontmatter:
 
 ```
-{{# frontmatter pick: title, tags #}}
+{# frontmatter pick: title, tags #}
 
 # {{title}}