Run in Eval mode

Use eval command to evaluate code snippets from CLI:

$ cr eval 'echo |demo'
1
took 0.07ms: nil

$ cr eval 'echo "|spaced string demo"'
spaced string demo
took 0.074ms: nil

Multi-line Code

You can run multiple expressions:

cr eval '
-> (range 10)
  map $ fn (x)
    * x x
'
# Output: calcit version: 0.5.25
# took 0.199ms: ([] 0 1 4 9 16 25 36 49 64 81)

Working with Context Files

Eval can access definitions from a loaded program:

# Load from specific file and eval with its context
cr demos/compact.cirru eval 'range 3'
# Output: ([] 0 1 2)

# Use let bindings
cr demos/compact.cirru eval 'let ((x 1)) (+ x 2)'
# Output: 3

Type Checking in Eval

Type annotations and static checks work in eval mode:

# Type mismatch will cause error
cr demos/compact.cirru eval 'let ((x 1)) (assert-type x :string) x'
# Error: Type mismatch...

# Correct type passes
cr demos/compact.cirru eval 'let ((x 1)) (assert-type x :number) x'
# Output: 1

Common Patterns

Quick Calculations

cr eval '+ 1 2 3 4'
# Output: 10

cr eval 'apply * $ range 1 6'
# Output: 120  ; factorial of 5

Testing Expressions

cr eval '&list:nth ([] :a :b :c) 1'
# Output: :b

cr eval '&map:get ({} (:x 1) (:y 2)) :x'
# Output: 1

Exploring Functions

# Check function signature
cr eval 'type-of range'
# Output: :fn

# Test with sample data
cr eval '-> (range 5) (map inc) (filter (fn (x) (> x 2)))'
# Output: ([] 3 4 5)

Important Notes

Syntax Considerations

  • No extra brackets: Cirru syntax doesn't need outer parentheses at top level

    • ✅ cr eval 'range 3'
    • ❌ cr eval '(range 3)' (adds extra nesting)

  • Let bindings: Use paired list format ((name value))

    • ✅ let ((x 1)) x
    • ❌ let (x 1) x (triggers "expects pairs in list for let" error)

Error Diagnostics

  • Type warnings cause eval to fail (intentional safety feature)
  • Check .calcit-error.cirru for complete stack traces
  • Use cr cirru parse-oneliner to debug parse issues

Query Examples

Use cr query examples to see usage examples:

cr demos/compact.cirru query examples calcit.core/let
cr demos/compact.cirru query examples calcit.core/defn