Documentation

Getting Started

Guides

Libraries

Standard Library (stdlib)

ansi ANSI color and terminal styling utilities
docserver Embedded documentation server with caching

Community Libraries (contrib)

azure-ai Azure OpenAI API for accessing GPT-4, Claude, and other hosted models
claude Anthropic Claude API integration with multi-turn conversations and tools
couchdb CouchDB database client with CRUD operations and Mango queries
deepseek DeepSeek LLM API idiomatic interface
groq Groq ultra-fast inference API
ollama Local LLMs through Ollama’s OpenAI-compatible API
openai OpenAI API with options-based interface
phospher Phospher Icons SVG inline icon fetcher
stripe Stripe payment processing API
svgraph SVG chart and graph generation
zlm “Zero Language Model” for testing LLM-scale scenarios without burning tokens

Language Keywords

Variables

var Variable declaration
raw Raw string/template modifier

Syntax

comments Using comments in code

Logic

if then elseif else end Conditional statements
end Block terminator keyword
and or not Logical AND, OR, and NOT

Loops

for in Loop with iteration
while do Loop while condition is true
break Exit loop early
continue Skip to next iteration

Functions

function Define a function
return Return from function

Exceptions

try Try-catch error handling
catch() Catch errors from try block
throw(msg) Throw an error with call stack information

Types

array Ordered list of values
binary Immutable binary data (files, images, etc.)
boolean True or false
code Pre-parsed source code value
error Error value with message and stack trace
nil Null/undefined value
number Floating-point number
object Key-value data structure
string Text value

Built-in Functions

Strings

contains(str, pattern) Check if contains pattern (supports regex)
find(str, pattern) Find all matches, returns array of {text, pos, len} objects (supports regex)
join(array, sep) Join array elements into single string
len(value) Get the length of arrays, objects, or strings
lower(str) Convert to lowercase
repeat(str, count) Repeat string multiple times
starts_with(str, prefix) Check if string starts with prefix
ends_with(str, suffix) Check if string ends with suffix
replace(str, pattern, replacement) Replace all matches of pattern with replacement string or function result (supports regex)
split(str, sep) Split string into array by separator
substr(str, pos, length) Get text, supports negative length
template(str) Create reusable template function from string with {{expression}} syntax
trim(str) Remove leading and trailing whitespace
upper(str) Convert to uppercase

Arrays & Objects

deep_copy(value) Deep copy of arrays/objects; functions removed (safety for scope boundaries)
filter(array, fn) Keep only elements matching predicate
keys(obj) Get array of all object keys
map(array, fn) Transform each element with function
pop(array) Remove and return last element
push(array, values...) Add elements to end, returns new length
range(start, end, step) Create array of numbers in sequence
reduce(array, fn, init) Combine array into single value
shift(array) Remove and return first element
sort(array, fn) Sort array in ascending order
unshift(array, values...) Add elements to beginning, returns new length
values(obj) Get array of all object values

Math

abs(n) Absolute value
ceil(n) Round up to nearest integer
clamp(val, min, max) Constrain value between min and max
floor(n) Round down to nearest integer
max(nums...) Find maximum value
min(nums...) Find minimum value
pow(base, exp) Raise to power (exponentiation)
random() Get random float between 0 and 1 (seeded per invocation)
round(n) Round to nearest integer
sqrt(n) Square root
acos(x) Inverse cosine (arccosine), x between -1 and 1, returns radians
asin(x) Inverse sine (arcsine), x between -1 and 1, returns radians
atan(x) Inverse tangent (arctangent), returns radians
atan2(y, x) Inverse tangent with quadrant correction, returns radians
sin(angle) Sine of angle in radians
cos(angle) Cosine of angle in radians
tan(angle) Tangent of angle in radians
exp(x) E raised to the power x
log(x) Logarithm base 10
ln(x) Natural logarithm (base e)
pi() Mathematical constant π (3.14159…)

File I/O

load(path) Read file contents as string
load_binary(path) Read file as immutable binary data
save(path, content) Write string to file (create/overwrite)
save_binary(binary, path) Write binary data to file
append_file(path, content) Append content to file (create if needed)
copy_file(src, dst) Copy file (supports /EMBED/ for embedded files)
move_file(src, dst) Move file from source to destination
rename_file(old, new) Rename or move a file
remove_file(path) Delete a file
list_dir(path) List directory contents with {name, is_dir}
list_files(path) List files in directory recursively
make_dir(path) Create directory (including parent directories)
remove_dir(path) Remove empty directory
file_exists(path) Check if file or directory exists
file_type(path) Get file type (“file” or “directory”)
current_dir() Get current working directory
watch(path, timeout) Monitor file or directory for changes

Network & HTTP

fetch(url, options) Make HTTP requests (JavaScript-style fetch API)
http_server(config) Create HTTP server for handling requests

I/O

input(prompt) Read line from stdin, optionally display prompt
print(values...) Output values to stdout, separated by spaces
write(values...) Output values to stdout without newline at the end
busy(message) Display a loading/busy message to stderr

Date & Time

format_time(timestamp, format) Format timestamp to string
now() Get current Unix timestamp in local timezone
timestamp(timezone) Get current Unix timestamp in UTC or a specific timezone/offset
timer() Get current time with sub-second precision for benchmarking
parse_time(str, format) Parse time string to timestamp
sleep(duration) Pause execution for duration in seconds (default: 1)

Encoding

encode_base64(str|binary) Encode string or binary to base64
decode_base64(str) Decode base64 string to binary
format_json(value, indent) Convert value to JSON string (stringifies binary, functions, errors)
parse_json(str) Parse JSON string
markdown_html(text, options) Render markdown to HTML
markdown_ansi(text, theme) Render markdown to ANSI terminal output with colors
markdown_text(text) Render markdown to plain text

Modules

include(path) Execute script in current scope
require(path) Load module in isolated scope, return exports

Types

tobool(value) Convert to boolean
tonumber(value) Convert to number
tostring(value) Convert to string
type(value) Get type name of variable

Flow & Concurrency

context() Get runtime context for a scripts or nil if unavailable
exit(value) Exit script with optional return value
parallel(fns) Execute functions concurrently
parse(source, metadata) Parse code string into code or error value (never throws)
run(script, context) Execute script synchronously and return result
spawn(script, context) Run script in background goroutine and return numeric process ID
kill(pid) Terminate a spawned process by PID

Debugging

breakpoint(args...) Pause execution and enter debug mode (enable with -debug)
watch(exprs...) Monitor expression values and break on changes (enable with -debug)
throw(msg) Throw an error with call stack information

Testing

assert(condition, message) Check a condition and throw an error if false

System & Data Storage

sql(namespace, config) Create or retrieve a MySQL-compatible database connection pool
datastore(namespace, config) Access a named thread-safe in-memory key/value store with optional persistence
sys(key) Access system information and CLI configuration values
doc(topic) Access documentation for modules and builtins
env(name) Read environment variable
uuid() Generate RFC 9562 UUID v7 (time-ordered, sortable unique identifier)

Security

hash(algo, data) Compute cryptographic hash of string or binary (sha256, sha512, sha1, md5)
hash_password(password, cost) Hash password with bcrypt for secure storage
verify_password(password, hash) Verify password against bcrypt hash
sign_rsa(data, private_key_pem) Sign data with RSA private key (SHA256-PKCS1v15)
verify_rsa(data, signature, public_key_pem) Verify RSA signature
rsa_from_jwk(n, e) Convert JWK modulus and exponent to PEM-encoded RSA public key
sign_ec(data, private_key_pem) Sign data with EC private key (ES256, P-256 curve)
verify_ec(data, signature, public_key_pem) Verify EC signature (ES256, P-256 curve)
ec_from_jwk(x, y) Convert JWK x,y coordinates to PEM-encoded EC public key (P-256)

Embedding

Learn about Embedding Duso in your Go applications.