Reader Syntax Entry: Real Literal

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Reader Syntax Entry: Real Literal

Name

Real Literal

Class

Reader Syntax

Concrete Syntax

real ::= sign? digit+ "." digit* exponent?
       | sign? digit+ exponent
exponent ::= ("e" | "E") sign? digit+

Constituents

  • optional sign
  • decimal digits
  • decimal point and/or scientific exponent

Description

A real literal denotes a double-precision floating-point number.

Acceptance Rules

  • documented examples include 3.1, 0.23, -56.123, 4.1e-6
  • numbers between -1 and 1 must contain a leading zero according to Autodesk prose

Strict/Lax Policy

  • strict: reject ambiguous forms such as .5 and 1. until product tests confirm them
  • lax: may accept host-confirmed forms beyond the conservative grammar

Examples

  • 1.0
  • 0.5
  • -3.25
  • 4.1e-6

Compatibility

  • AutoCAD 2021+ Unicode changes do not directly alter numeric tokens, but reader changes should still be version-qualified

Notes

The published documentation leaves .5, 1., and some exponent variants under-specified.

Availability

  • AutoCAD 2026: documented (per Autodesk reference page).
  • BricsCAD V26: presumed compatible (no contradicting page found).
  • Status: AutoCAD documented; BricsCAD presumed-both pending Phase 4 verification.

Source Notes