Skip to content

TemplateParser.md

Latest commit

 

History

History
157 lines (133 loc) · 3.6 KB

TemplateParser.md

File metadata and controls

157 lines (133 loc) · 3.6 KB

ABAP Template Parser Documentation

A simple jinja-like template parser is available via class zcl_llm_template_parser. The main use case is to simplify template usage with the llm client and further features.

Basic Usage

DATA(parser) = NEW zcl_llm_template_parser( ).
parser->add_template( 
    name    = 'mytemplate'
    content = 'Hello {{ name }}!' ).
DATA(result) = parser->render( 
    template_name = 'mytemplate'
    context      = lr_data ).

Template Syntax

Variables

{{ variable }}                "Basic variable
{{ user.name }}              "Nested property
{{ users[0].name }}          "Array/table access
{{ items[1].details.price }} "Combined access

Variable Filters

Available filters are:

{{ name|upper }}            "Convert to uppercase
{{ name|lower }}            "Convert to lowercase
{{ name|capitalize }}       "Capitalize first letter
{{ name|default("value") }} "Use default if value is empty

Control Structures

If Statements

{% if condition %}
  content
{% elif other_condition %}
  alternative
{% else %}
  default content
{% endif %}

Supported Conditions:

  • Comparison Operators: ==, !=, >=, <=, >, <
  • Logical Operators: and, or, not
  • Boolean Values: true, false, 1, 0, X, x

Examples:

{% if user.age > 18 %}
  Adult content
{% endif %}

{% if not is_active %}
  Account inactive
{% endif %}

{% if status == 'valid' and count > 0 %}
  Valid and not empty
{% endif %}

For Loops

{% for item in items %}
  {{ item.name }}
{% endfor %}

Loop Context Variables:

{{ loop.index }} "Current iteration (1-based)
{{ loop.first }} "True if first iteration
{{ loop.last }}  "True if last iteration

Comments

{# This is a comment and will not appear in output #}

Data Type Support

Elementary Types

  • Strings
  • Integers
  • Dates (formatted in user format)
  • Times (formatted in user format)
  • Boolean values (output as 'true'/'false')

Complex Types

  • Structures
  • Tables
  • Nested structures and tables

Table Output Formatting

Direct table reference formatting:

  • Elementary tables: comma-separated list
  • Structure tables: [KEY1: value1, KEY2: value2; KEY1: value1, KEY2: value2]
  • Nested tables: [NESTED TABLE]

Special Characters

Escape sequences supported:

\n     "Newline
\t     "Tab
\{     "Literal curly brace
\}     "Literal curly brace
\\     "Literal backslash

Error Handling

The parser raises ZCX_LLM_TEMPLATE_PARSER exception for:

  • Invalid template syntax
  • Unclosed tokens
  • Invalid variable paths
  • Missing templates
  • Unsupported variable types
  • Invalid loop syntax
  • Invalid conditions
  • Invalid table indexes

Complete Example

DATA(template) =
  |{% if user.active %}| &&
  |  Welcome {{ user.name|capitalize }}!\n| &&
  |  Your recent orders:\n| &&
  |  {% for order in user.orders %}| &&
  |    {% if loop.first %}First order:{% endif %}| &&
  |    {{ loop.index }}. {{ order.product }} ({{ order.date }})\n| &&
  |  {% endfor %}| &&
  |{% else %}| &&
  |  Account inactive| &&
  |{% endif %}|.

DATA(parser) = NEW zcl_llm_template_parser( ).
parser->add_template( name = 'welcome' content = template ).
DATA(output) = parser->render( 
    template_name = 'welcome'
    context      = user_data ).

Limitations

  • No custom filters supported
  • No template inheritance or includes
  • No whitespace control
  • No complex table operations (sorting, filtering, etc.)
  • No arithmetic operations in expressions
  • No inline expressions

This documentation covers all currently implemented features in the template parser class.