Examples

This page collects complete Wist programs and shows which dialect shape they belong to.

Use these examples as small executable references, not as a full language specification.

When to read this page

Read this page after the Syntax Tour when you want complete snippets that can be copied into examples, tests or dialect documentation.

Goal

Connect Wist syntax examples to the dialects and modules that make them valid.

Minimal arithmetic

Program:

2 + 3 * 4

Expected result:

14

Typical dialect:

dialect MinimalArithmetic
use Arithmetic,Numbers,Scopes,Whitespaces
backend interpreter

This is the best first example because it proves that the basic parser, arithmetic modules and interpreter path are working.

Grouped arithmetic

Program:

(2 + 3) * 4

Expected result:

20

Use this when documenting precedence and grouping.

Variables and reassignment

Program:

let x = 5
x = x + 1
x

Expected result:

6

Typical modules:

use Arithmetic,Numbers,Identifier,Variables,Scopes,Whitespaces

This example proves that declaration, lookup and reassignment work together.

Variable-based formula

Program:

price + fee * 2

With inputs:

price = 100
fee = 5

Expected result:

110

This is useful for pricing-style DSLs. Keep the dialect narrow and avoid enabling unrelated runtime features.

Conditional expression

Program:

let x = 2
if x == 2 (10) else (20)

Expected result:

10

Typical modules:

use Conditions,Equality,Arithmetic,Numbers,Identifier,Variables,Scopes,Whitespaces

Add ComparisonConditions when using operators such as <, <=, > or >=.

While loop accumulator

Program:

let sum = 0
let i = 1

while i <= 5 (
    sum = sum + i
    i = i + 1
)

sum

Expected result:

15

The while condition does not have to be parenthesized when it parses as one expression node. The loop body remains grouped because it contains multiple operations.

Typical modules:

use Loops,Variables,Identifier,Arithmetic,Numbers,ComparisonConditions,Scopes,Whitespaces

Use this to test loop execution, variable mutation and backend parity.

Full default for example

Program:

let sum = 0

for (let i = 1) (i <= 5) (i = i + 1) (
    sum = sum + i
)

sum

Expected result:

15

This is the shipped full-default example shape. It is useful for validating a broader Wist dialect over both interpreter and CIL modes. The current for parser expects initialization, condition, update and body to be grouped.

Nested loop aggregate

Program:

let total = 0
let outer = 1

while outer <= 3 (
    let inner = 1
    while inner <= 2 (
        total = total + (outer * inner)
        inner = inner + 1
    )
    outer = outer + 1
)

total

Expected result:

18

Use this only for dialects that intentionally allow nested loops, local declarations and mutation.

Interop expression in trusted profiles

Program:

NumbersModule.Core.RealNumberImpl.Add(2, 5)

Expected result:

7

This belongs to trusted full profiles that include CSharpInterop. Do not use this example for restricted formula dialects.

Choosing examples for documentation

Use the smallest example that proves the concept:

Concept	Recommended example
First run	2 + 3 * 4
Grouping	(2 + 3) * 4
Variables	let x = 5; x = x + 1; x
Conditions	if x == 2 (10) else (20)
Loops	sum from 1 to 5
Backend parity	same arithmetic/loop source in both modes
Restricted formula DSL	price + fee * 2

Common mistakes

• Using a broad full-default example to document a restricted DSL.
• Showing interop in user-facing formula documentation.
• Using loop examples before explaining variables and comparisons.
• Treating parenthesized while conditions as the only valid form.
• Forgetting to mention which dialect or modules make an example valid.
• Treating examples as complete language specification.

Next

Continue with Build DSLs to turn these examples into explicit dialect profiles.