Components of SDTL

SDTL Command Language

There are 71 SDTL composite types, which fall into four groups.

  • Transformation commands
  • Informational commands
  • Expressions
  • Complex properties

SDTL has been implemented in JSON schemas, but it can be serialized to XML and other formats. The SDTL Command Language is available in several formats at For documentation of each element in SDTL see: .

SDTL Function Library

Like most computer languages, SDTL uses functions for common computations, such as trigonometric (sine, cosine, etc.) and statistical (normal, binomial, gamma, etc.) functions. The Function Library provides a crosswalk between the SDTL version of each function and the same function in each source language. These crosswalks allow applications that translate source languages into SDTL to apply the same code to almost all functions. The Function Library is provided in a JSON schema, which is available for download at

SDTL Pseudocode Library Schema

The Pseudocode Library Schema provides a simple way to translate SDTL JSON into natural language. A Pseudocode Library consists of templates providing text that should surround the properties of each SDTL type. An SDTL command is translated by resolving each property into text and inserting it in the template. For example, the template for the SDTL Compute command is:

Set {variable} to {expression}.

The {variable} property resolves to a variable name, and the {expression} property resolves to an expression, which may include variables, numeric constants, and mathematical or string functions. The result of inserting values for {variable} and {expression} into the template will be something like:

Set varY to the natural logarithm of varX.

The current version of the Pseudocode Library is available at: