# Memelang v5 Memelang is an concise query language for structured data, knowledge graphs, retrieval-augmented generation, and semantic data. See the [Python GitHub repository](https://github.com/memelang-net/memesql5/). ### Memes A meme comprises key-value pairs separated by spaces, starting with `m=int`, and ending with a semicolon. A meme is analogous to a relational database row. ``` m=123 R1=A1 R2=A2 R3=A3; ``` * ***M-identifier***: an arbitrary integer in the form `m=123`, analogous to a primary key * ***R-relation***: an alphanumeric key analogous to a database column * ***A-value***: an integer, decimal, or string analogous to a database cell value * Non-alphanumeric strings are double-quoted, with CSV-style quote escaping `="John ""Jack"" Kennedy"` * Comments are prefixed with double forward slashes `//` ``` // Example memes for the Star Wars cast m=123 actor="Mark Hamill" role="Luke Skywalker" movie="Star Wars" rating=4.5; m=456 actor="Harrison Ford" role="Han Solo" movie="Star Wars" rating=4.6; m=789 actor="Carrie Fisher" role=Leia movie="Star Wars" rating=4.2; ``` ### Queries Queries are partial memes with empty parts as wildcards: * Empty A-values retrieve all values for the specified R-relation * Empty R-relations retrieve all relations for the specified A-value * Empty R-relations and A-values (` = `) retrieve all pairs in the meme ``` // Query for all movies with Mark Hamill as an actor actor="Mark Hamill" movie=; // Query for all relations involving Mark Hamill ="Mark Hamill"; // Query for all relations and values from all memes relating to Mark Hamill: ="Mark Hamill" =; ``` A-value operators: * String: `=`, `!=` * Numerics: `=`, `!=`, `>`, `>=`, `<`, `<=` ``` firstName=Joe; lastName!="David-Smith"; height>=1.6; width<2; weight!=150; ``` Comma-separated values produce an ***OR*** list: ``` // Query for (actor OR producer) = (Mark OR "Mark Hamill") actor,producer=Mark,"Mark Hamill" ``` R-relation operators: * `!` negates the relation name ``` // Query for Mark Hamill's non-acting relations !actor="Mark Hamill"; // Query for an actor who is not Mark Hamill actor!="Mark Hamill"; // Query all relations excluding actor and producer for Mark Hamill !actor,producer="Mark Hamill" ``` ### A-Joins Open brackets `R1[R2` join memes with equal `R1` and `R2` A-values. Open brackets need **not** be closed, a semicolon closes all brackets. ``` // Generic example R1=A1 R2[R3 R4>A4 A5=; // Query for all of Mark Hamill's costars actor="Mark Hamill" movie[movie actor=; // Query for all movies in which both Mark Hamill and Carrie Fisher act together actor="Mark Hamill" movie[movie actor="Carrie Fisher"; // Query for anyone who is both an actor and a producer actor[producer; // Query for a second cousin: child's parent's cousin's child child= parent[cousin parent[child; // Join any A-Value from the present meme to that A-Value in another meme R1=A1 [ R2=A2 ``` Joined queries return one meme with multiple `m=` M-identifiers. Each `R=A` belongs to the preceding `m=` meme. ``` m=123 actor="Mark Hamill" movie="Star Wars" m=456 movie="Star Wars" actor="Harrison Ford"; ``` ### Variables R-relations and A-values may be certain variable symbols. Variables *cannot* be inside quotes. * `@` Last matching A‑value * `%` Last matching R‑relation * `#` Current M-identifier ``` // Join two different memes where R1 and R2 have the same A-value (equivalent to R1[R2) R1= m!=# R2=@; // Two different R-relations have the same A-value R1= R2=@; // The first A-value is the second R-relation R1= @=A2; // The first R-relation equals the second A-value =A1 R2=%; // The pattern is run twice (redundant) R1=A1 %=@; // The second A-value may be Jeff or the previous A-value R1=A1 R2=Jeff,@; ``` ### M-Joins Explicit joins are controlled using `m` and `#`. * `m=#` present meme (implicit default) * `m!=#` join to a different meme * `m= ` join to any meme (including the present) * `m=^#` (or `]`) resets `m` and `#` to the *previous* meme, acts as *un*join ``` // Join two different memes where R1 and R2 have the same A-value (equivalent to R1[R2) R1= m!=# R2=@; // Join any memes (including the present one) where R1 and R2 have the same A-value R1= m= R2=@; // Join two different memes, unjoin, join a third meme (equivalent statements) R1[R2] R3[R4; R1= m!=# R2=@ m=^# R3= m!=# R4=@; // Unjoins may be sequential (equivalent statements) R1[R2 R3[R4]] R5=; R1= m!=# R2=@ R3= m!=# R4=@ m=^# m=^# R5=; R1= m!=# R2=@ R3= m!=# R4=@ m=^# ] R5=; R1= m!=# R2=@ R3= m!=# R4=@ ]] R5=; // Join two different memes on R1=R2, unjoin, then join the first meme to another where R4=R5 R1= m!=# R2=@ R3= m=^# R4= m!=# R5=@; // Query for a meta-meme, R2's A-value is R1's M-identifier R1=A1 m= R2=# ``` ### About Memelang was created by [Bri Holt](https://en.wikipedia.org/wiki/Bri_Holt) and first disclosed in a [2023 U.S. Provisional Patent application](https://patents.google.com/patent/US20250068615A1). ©2025 HOLTWORK LLC. Contact [info@memelang.net](mailto:info@memelang.net).