Month: October 2019

Recently GNOME Calculator has gained a library for math expression parsing and calculation, as a parallel effort to the one used internally for the application, called GCalc.

While GCalc allows to take a string to create an object oriented representation of it and can perform multi-precision calculations, this feature was unable to be used outside, just VDA is using it for math expression parsing, but no-more, yet.

In order to expose GCalc features to user oriented applications, now a new library called GCi was added. GCi provides, for now, a controller for GTK Entries.

GTK Entries controller in GCi, can add calculation features to your Entry. Once you have created a GCi.EntryController and set its entry property to the one in your UI application, a secondary icon using a calculator is added, while allows your users to  write =8*2+1, hit enter or click on the secondary icon and the math expression is replaced by its calculation result (and yes you should use = in order to establish it as a math expression to replace).

Vala Data Access library has reached a 0.90 Beta 1 release.

VDA provides a set of interfaces to wraps database connection, execution of SQL commands and access to returned values of the queries. Read the previous introduction post.

This version supports:

• First Beta version of VDA
• Native implementation for PostgreSQL
• GDA implementation with support for SQLite and PosgreSQL
• Basic SqlValue implementation and conversion between values
• Basic SQL commands parsing support for SELECT, INSERT, DELETE, UPDATE, using parameters in order to provide the values required to execute it
• Object Oriented API for SQL commands: SELECT, INSERT, DELETE, UPDATE
• Support for Parameters in queries using GDA declaration syntax
• SQL command parsing use GCalc from GNOME Calculator
• Async queries execution
• Support to map Row’s values to GObject based classes’ properties using DataObject interface
• Support for row modification/insert using DataObject interface
• DataObject supports Vda.SqlValue properties, both generic or specific
• DataObject support conversion between Vda.SqlValue values and between basic properties’ types like string, int, double, float, bool

No pre-releases was made, because the API was changed while implementing database providers and included most of the interfaces to implement for better more powerful features.

VDA return Vda.SqlValue objects when you access a Table’s row’s column’s value; the provider is responsible to create it when is requested, so no overhead is present for SQL queries execution.