RecallRecall, 594 bytes
In short: Recall has no arithmetic operators in a classic sense, it only has bitwise operations. You can not just "add one" etc. Recall is also strictly stack-based.
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Example 1: Print something
Input:
-[--->+<]>-----..-[----->+<]>.++++.+[->++++<]>.---[----->++<]>.---.------------.++++++++.++++++++.+[-->+++++<]>-.
Output:
PPCG rocks!
Example 2: Output square numbers up to 100
Input:
+[>++<-]>[<+++++>-]+<+[>[>+>+<<-]++>>[<<+>>-]>>>[-]++>[-]+>>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]<<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]
Output:
0
1
4
9
16
25
36
49
64
81
100
This example might take a few minuted to execute and might cause a "this tab is frozen" message. Ignore that and wait.