Leia Tagged Dialects

The registry table is generated from the current leia binary dialect registry; explanatory sections below are maintained with the generated reference.

Leia supports DSL-native tagged dialects for compact host automation, data format handling, web routing, spreadsheets, and optional LLM integrations. A dialect is an explicit tagged expression that returns an ordinary Leia value.

Forms

name := "Leia"
status := sh`git status --short`
checked := sh!`printf checked`
argv_checked := cmd!`printf checked`
out := $`printf hello`
files := glob`examples/**/*.leia`
data := json`{"name": ${name}}`
summarizer := agent {
    name: "summary_agent"
    config: func(summary) {
        return {model: "example-model", user: summary}, nil
    }
    params: ["summary"]
}

${expr} is the interpolation form inside tagged strings. Each dialect decides how interpolated values are encoded. tag! is the fail-fast form for dialects that support recoverable errors; sh! and cmd! raise on non-zero command exits while preserving the same result shape for successful commands.

Built-In Dialects

Tag	Category	Eval	Block	Capabilities	Aliases
`agent`	`llm`	false	true	llm.turn	none
`base32`	`data`	true	false	none	none
`base64`	`data`	true	false	none	none
`binary`	`data`	true	false	none	none
`cidr`	`protocol`	true	false	none	none
`cmd`	`host`	true	false	process.exec, env.write	none
`cookie`	`protocol`	true	true	none	cookies
`cookies`	`protocol`	true	true	none	cookie
`csv`	`text`	true	true	none	none
`deflate`	`data`	true	false	none	none
`duration`	`text`	true	true	none	none
`emailaddr`	`protocol`	true	true	none	mailaddr
`env`	`host`	true	true	env.read	none
`excel`	`data`	true	false	none	xlsx
`form`	`protocol`	true	true	none	urlform
`glob`	`host`	true	false	fs.read	none
`gzip`	`data`	true	false	none	none
`hash`	`data`	true	false	none	none
`headers`	`protocol`	true	true	none	http_headers
`hex`	`data`	true	false	none	none
`hostport`	`protocol`	true	false	none	none
`html`	`protocol`	true	true	none	none
`html_escape`	`protocol`	true	false	none	none
`http_headers`	`protocol`	true	true	none	headers
`httpmsg`	`protocol`	true	true	none	none
`ini`	`text`	true	true	none	none
`ipaddr`	`protocol`	true	false	none	none
`json`	`text`	true	true	none	none
`jsonl`	`text`	true	true	none	none
`jsonptr`	`text`	true	true	none	none
`junit`	`compat`	true	false	none	none
`jwt`	`protocol`	true	true	none	none
`kv`	`text`	true	true	none	none
`lines`	`text`	true	false	none	split
`logfmt`	`text`	true	true	none	none
`mailaddr`	`protocol`	true	true	none	emailaddr
`markdown`	`text`	true	true	none	md
`md`	`text`	true	true	none	markdown
`mdtable`	`text`	true	true	none	none
`mime`	`protocol`	true	true	none	none
`model`	`llm`	false	true	llm.turn	none
`multipart`	`protocol`	true	true	none	none
`numbers`	`text`	true	false	none	nums
`nums`	`text`	true	false	none	numbers
`path`	`text`	true	false	none	none
`pem`	`data`	true	false	none	none
`prompt`	`llm`	true	true	none	none
`quote`	`llm`	true	true	none	none
`re`	`text`	true	false	none	regexp
`regexp`	`text`	true	false	none	re
`rfc3339`	`text`	true	true	none	timestamp
`semver`	`text`	true	true	none	none
`serve`	`web`	true	true	net.listen	none
`sh`	`host`	true	false	process.shell	none
`shellwords`	`text`	true	true	none	none
`split`	`text`	true	false	none	lines
`sql`	`database`	true	true	none	none
`sse`	`protocol`	true	true	none	none
`tap`	`text`	true	true	none	none
`template`	`text`	true	true	none	none
`timestamp`	`text`	true	true	none	rfc3339
`tool`	`llm`	false	true	llm.turn	none
`tsv`	`text`	true	true	none	none
`turn`	`llm`	false	true	llm.turn	none
`url`	`protocol`	true	false	none	none
`urlform`	`protocol`	true	true	none	form
`urlpath`	`protocol`	true	true	none	none
`urlquery`	`protocol`	true	true	none	none
`uuid`	`data`	true	false	none	none
`words`	`text`	true	false	none	none
`xlsx`	`data`	true	false	none	excel
`xml`	`text`	true	true	none	none
`yaml`	`text`	true	true	none	yml
`yml`	`text`	true	true	none	yaml
`zlib`	`data`	true	false	none	none

Capability Categories

Host automation tags such as sh, cmd, glob, and env use host filesystem, process, or environment capabilities.
Web and network-facing tags such as serve must be denied when the embedding host has not granted the relevant network capability.
Optional LLM tags such as model, turn, tool, and agent use the same llm.turn policy as the llm standard library.
Pure text, protocol, and data tags return ordinary values and should be documented with runnable examples before being treated as stable public surface.

Important Result Shapes

Dialect	Result shape
`sh`, `$`	Command result table with `ok`, `code`, `stdout`, `stderr`, and `text`.
`cmd`	Argv-safe command result table with the same command result shape as `sh`.
`glob`	Sorted path array.
`sql`	`{query, args, names}` with named parameters lowered to positional placeholders.
`xlsx` encode	Workbook byte string suitable for writing or decoding with `excel`.
`excel` decode	Row array; with `{headers: true}`, rows are tables keyed by the first worksheet row.
`serve`	Route server descriptor/loopback result as documented by runnable web examples.
`turn`	`(result, err)` for a single LLM provider request.
`agent`	Callable agent value.

Examples

go run ./cmd/leia examples check examples/hello/dialects.leia examples/dialects/text_parsing.leia
go run ./cmd/leia examples run repo-dialects-data_aggregation_report

The focused examples below show shell/process, data-format, spreadsheet, AI, and web dialect surfaces in small runnable programs.

Additional focused evidence lives in:

examples/dialects/ai_prompt_quote.leia for prompt and quote tags.
examples/dialects/data_aggregation_report.leia for mixed data-format tags.
examples/dialects/http_protocol_trace.leia and examples/dialects/network_protocols.leia for web/protocol tags.
examples/web/serve_dialect_app.leia and examples/web/route_workbench.leia for route/server evidence.