lambe 0.1.0

Query JSON, YAML, TOML, and HCL files with a composable pipeline DSL. Like jq but multi-format, with cleaner syntax. CLI tool + Dart library + MCP server for AI agents.

0.1.0

Core

• Query AST: sealed LamExpr hierarchy (16 subtypes) + sealed PipeOp (24 subtypes)
• Left-recursive parser via Rumil's rule() + Warth seed-growth
• Operator precedence via layered chainl1 calls
• Null propagation: navigation propagates null, computation throws on type errors
• Tolerant parsing via .recover() for REPL completion and multi-line detection

Query Language

• Property access chains: .users[0].address.city
• Negative indexing: .items[-1]
• String key indexing: .data["key"]
• Slicing: .[1:3], .[:3], .[2:], .[:-1]
• Arithmetic: +, -, *, /, %
• Comparison: <, <=, >, >=, ==, !=
• Boolean logic: &&, ||, !
• Object construction with shorthand: {name, total: .price * .qty}
• Conditionals: if .age > 65 then "senior" else "active"
• String interpolation: "\(.name) is \(.age) years old"

Pipeline Operations (24)

• Filter and transform: filter, map
• Ordering: sort, sort_by, reverse
• Grouping: group_by (returns {key, values} structure)
• Deduplication: unique, unique_by
• Structure: flatten, keys, values, length, first, last
• Aggregation: sum, avg, min, max
• Map operations: filter_values, map_values, filter_keys
• Existence: has
• Entry conversion: to_entries, from_entries

Multi-format I/O

• Input: JSON, YAML, TOML, HCL, XML, CSV, TSV with auto-detection
• Output: --to json/yaml/toml/xml/csv for format conversion
• --schema for data structure inference
• --assert for CI/CD validation (exit 0 if true, 1 if false)

Interactive REPL (lam -i)

• Parser-driven tab completion on field names, pipeline operations, and inner fields
• Syntax highlighting and colorized JSON output
• Persistent history (~/.lambe_history) with Ctrl+R reverse search
• Multi-line input with \ continuation and parser-driven bracket detection
• Ctrl+Left/Right word movement, Ctrl+A/E/K/U editing shortcuts
• REPL commands: :schema, :to, :raw, :pretty, :load, :history, :help, :quit

API

• Library: query(), queryJson(), queryString(), parse(), eval()
• Output: formatOutput(), inferSchema()
• CLI: lam '<expression>' [file] with all flags
• MCP server: lambe_query, lambe_schema, lambe_assert tools

Ecosystem

• lambe_test package with matchers: lamWhere, lamEquals, lamMatches, lamHas
• MCP server installable via dart pub global activate lambe → lam-mcp